He has quietly flown into this city burgeoning with Latin exiles in search of money and recruits -- a trim, intense man with a full beard, a wisp of Castillian in his Spanish and two bodyguards.

The bodyguards watch his back as he roams about at night, darting glances at shadows for the Cuban and Sandinista assassins he fears have written his name on their bullets.

On his last trip, they missed him, he says. Moments after he made his pitch to Nicaraguan exiles for support a safe house was machine-gunned. Police have no record of the incident, but concede it is possible. In Miami, many shots are fired in the night that go unreported.

Exile politics here can be a treacherous game for men like Pedro Ortega, 46, a Spanish-born Nicaraguan businessman who claims he commands 6,000 armed troops inside Nicaragua and along the Honduran border.

The claim is possible, but improbable. But Ortega is a prominent member of a small cadre of self-styled counterrevolutionary leaders whose avowed aim is to drive all communists out of Nicaragua.

He has come to Miami because it is more than just a center for Latin exiles, more than just a haven for anti-Castro Cubans, but also a training ground for small groups of men who are preparing to invade their homelands, much as exiles from Fidel Castro's Cuba did two decades ago, to "liberate" their people.

Other groups of exiles pursue the same goal, from bases in Honduras, possibly in Guatemala and in other Central American countries. They campaign for money and support among poor Nicaraguan exiles as well as in the comfortable homes of wealthy emigres who escaped Anastasio Somoza's fall with suitcases of cash.

In Miami, Ortega hawks the domino theory:

"If we don't save Nicaragua from communism, El Salvador will fall," Ortega said in the first interview he has granted a U.S. newspaper. "Later will come Guatemala and Honduras. And in a short time, Mexico. There is grave risk. All of Central America and the Caribbean will become a satellite of Russia and Cuba unless America wakes up."

The Nicaraguan exiles interpret social and political unrest back home as signs of imminent rejection of the Sandinista leadership, which they insist is communist-backed. And they interpret President Reagan's tough policy toward the Sandinistas as tacit approval for their cause.

The Reagan administration has cut off aid to Nicaragua, basing its action on the nation's alleged "involvement" in sending arms to guerrillas in El Salvador, but it has never openly supported the Nicaraguan opposition groups or any efforts to overthrow the Sandanistas.

On some trips, Ortega treks to a commando training camp in the Everglades, where the FBI has counted as many as 200 Nicaraguans training alongside anti-Castro Cubans for the "war of liberation" they hope will come.

Some of the young exiles say they work odd jobs until they have earned enough money ($350) for plane fare to Honduras, where they join Ortega or rival groups to fight the Sandinistas.

To his men -- mostly former National Guard soldiers who fled across the border when Somoza fell -- Ortega is Cmdr. Juan Carlos, a nom de guerre adopted by the former match factory magnate from Managua.

By his account, he has spent more than $1 million of his own money to round up soldiers for the National Liberation Army and keep his troops and other refugees in food, medicine and guns. To them, he is a hero, the only hope of going home again.

But to the government, he is a terrorist, assailed as the "leader of jackals" in La Barricada, the official newspaper -- a Somoza supporter who would turn the clock back to the harsh rule of the late dictator.

Ortega denies it. He only wants what his people want, he says, democracy, not communism. He promises to turn the government over to civilians for free elections once the Sandinistas are driven out "by bullets, the only language they understand."

He claims his soldiers have killed more than 300 government troops. He has lost only 25 men, he says, claiming more than 20,000 armed sympathizers inside the country -- a figure the government disputes -- ready to rise up alongside the people when they decide they can't take it anymore.

His claims multiply upon themselves: high body counts, low casualties, $1 million of his own money, 6,000 armed followers. They seem exaggerated. And even $1 million to feed and equip 6,000 soldiers amounts to only $166 per man -- not enough, even at Nicaraguan prices.

It is past midnight. An aide de camp, Capt. Fantomes (no first name offered) hops up from a bed and salutes. "El Jefe," he says. "I am off to make contact." And he disappears into the night. His mission: to debrief what he says are two Sandinista collaborators, "high government officials" Ortega claims who flew to Miami to funnel him military and political secrets as moles for his cause.

Come morning, he will begin courting some of the 600 ex-soldiers among the 20,000 Nicaraguans who have arrived here since Somoza's downfall two years ago. They are small businessmen, coffee growers, doctors, lawyers and bureaucrats who nervously await a State Department ruling on their political asylum requests.

Ortega must compete for the support of the exiles. There are two major rival groups -- one comprising former members of Somoza's National Guard, like Ortega, and one comprising former Sandinista backers. The groups agree on the goal of overthrowing the government, but on little else.

"At this time, we are not all united," Ortega concedes. "But we are calling for all Nicaraguans to forget the hate and the little wars we have fought among ourselves. We want the left, the right, Somozistas, everyone, to put aside their differences and come together."

"It will never happen," asserts rival exile leader Jose Francisco Cardenal. "Ortega hasn't realized the people hate his men. They haven't forgotten how the guard bombed the cities and defended a dictator to the last minute."

He is portly, 42, and, like most exiles, embittered. His wife works in a Miami dress shop to support his politics.

A former Managua builder with anti-Somoza credentials, he resigned as a private sector representative to the legislative council under the Sandinistas and fled. "My best friends are either in jail, dead or escaped to Miami," he said.

Some say he left because his business was going down the tube. He says business was booming, that the government had offered him an $8 million cost-plus contract to build a hospital "to try and buy me."

A leader of the Nicaraguan Democratic Union (NDU), an anti-Somoza group with more apparent political than military clout, Cardenal preaches to colleges, Lion's clubs, anyone who will listen. He works for Edmundo Chamorro, founder of the NDU and cousin of the assassinated publisher and revolutionary martyr, Pedro Joaquin Chamorro. His message differs little from Ortega's anti-communism.

The only way to get Nicaragua back, he says, is through a popular uprising he sees looming, fueled by about 2,000 NDU soldiers inside Nicaragua. Taking exiles' claims at face value, this force is substantially smaller than Ortega's, a reporter points out. Cardenal's face turns red.

"Go inside Nicaragua and ask the people what they think of the officers who fled and left troops behind. They will tell you, 'They ran.' Would you follow anyone who abandoned ship before?"

That is the big question in exile, argued at every turn.

Leaders like Cardenal scoff that no matter how fed up Nicaraguans are with the Sandinistas' ties to Fidel Castro and Cuba, the troubled economy, the banning of popular priests from television Masses, they will never join behind a movement whose army consists of former guardsmen.

The Sandinistas' ambassador to the United States agrees. "Nothing would consolidate our government more than an invasion by Somozistas," says Arturo Cruz. "It would be a kiss from heaven."

Ortega fires back: "Neither Cardenal or Chamorro can recover Nicaragua with words alone." Only his soldiers in exile are trained to tackle a war. "Who else can liberate the country? Do they want the U.S. Marines?"

He insists that none of the corrupt, old guard populate his ranks, only "young, honest, clean" officers. "We have nothing to do with those elements in the former government. People in Nicaragua are giving us food and protection and writing all our slogans on the walls. We don't feel we are still hated."

Exiles like Alberto Narvaez, 35, stream into the concrete building on Flagler Street, past the poster of Castro with bloody fangs, into the office for the Humanitarian Committee for Nicaraguan Refugees. Here, they sign up for political asylum and get a primer on life in the United States.

A former lieutenant with the National Guard, he lives in a room next door -- gratis from the private relief agency -- with his wife, Nubia, their two sons and an ex-sergeant's family of seven.

It is cramped and hot inside, with beds jammed together amidst boxes of cornflakes, bicycles, baby bottles and a refrigerator. Flies buzz about a chicken stew. Fried plantains simmer on a hot plate. A counterrevolution long on emotion, short on guns.

Two years back, Narvaez fought in the south against the Sandinistas. Then, he learned Somoza had fallen, and fled with his family and about 400 other National Guardsmen in a boat to El Salvador. No one ate or drank for three days. They were attacked and five people died.

For 18 months, Narvaez ran from country to country. Finally, he slipped across the border into Texas, where a son was born Feb. 5, on the side of a turnpike.

He named the boy Ronald Reagan Narvaez. Friends sent money. They took a bus to Miami. He found a job as a security guard, then as a $3.50-an-hour hotel janitor.

A baby wails. It is Ronald, age six months. "We named him after the president because he has great respect for the Nicaraguan people," says Narvaez, proudly bouncing his son. "We have great hope President Reagan will help us return to our country some day, free from Sandinistas."

Narvaez would go back to fight "in a minute" if the United States decided to back the exile groups with arms or money, or if the groups merged "into one strong group. Many others feel the same way. But now the groups are too splintered."

Two miles down a rutted dirt road, past a stern-faced armed sentry in jungle fatigues, a squad of two dozen anti-Castro Cubans, AR15 rifles at the ready, breaks from the savanna grass at a hard trot.

They are comrades in spirit with some 80 Nicaraguans -- many of them former guardsmen -- who practiced tactics and crawled around on their bellies in the swamp one recent Sunday for visitors at Campo Cuba, a guerrilla training site on 67 private acres in the Everglades, 10 miles from Miami International Airport.

Jorge Gonzales, the camp commander, is a Bay of Pigs realist long on bravado who concedes invading Cuba is foolhardy, that it is easier to stop Castro in Nicaragua. "Communism in Nicaragua is even more dangerous than Cuba," he said. "It is the bridge to Mexico." So he has thrown the welcome mat out for three rival Nicaraguan exile groups whose members train periodically.

"Juan Carlos has recruited many men at the camp," he said. "Many have gone on to Nicaragua to fight against the Sandinstas. None have come back here."

Gonzales, runs the largest of five anti-Castro training camps authorities say have sprung up in Dade County in the last year.

At Campo Cuba, "we make them lean; we send them to other camps to make them mean," says an ex-special forces sergeant, a volunteer instructor. He claims other camps are located elsewhere in the Caribbean.

Nicaragua has lodged official protests with the United States over the camp, charging violations of the Neutrality Act. "We get the impression that the U.S. feels what they are doing is all right," says Arturo Cruz, Nicaragua's U.S. ambassador. "Otherwise, they would come down hard on the camps. They are training openly."

But the FBI says no laws are being violated as long as the commandos train on private property with registered weapons and refrain from using the United States as a jumping off point for an invasion.

The biggest danger is not from authorities, Gonzales says, but from enemy agents he believes are hiding behind every palmetto, and joy riders out to spook the troops with wild fire from speeding cars. Suddenly, there is the crack of rifle fire and a scream.

Gonzales and a half-dozen others jam clips into their rifles and tear off toward the sound of shots.

Rafael, a lookout who is naked from the waist up, scrambles up a tall Florida pine, a .45 jammed into green fatigues. Bullets zing through the bush near camp headquarters, as close as 15 feet from visitors huddled behind the base of a tree.

"How many rounds you got left?" shouts Henry Perez, 30, an engineer who doubles as Gonzales' press attache.

"Three shots left!" yells Rafael. Rifles pop in the distance. Perez disappears into the trailer to call police.

Later, authorities say they have no record of the incident, and suggest it was perhaps staged for reporters.