The two Americans killed in a clash with government troops in Nicaragua last Saturday were Vietnam veterans who traveled to Central America at their own expense to "fight communism," the leader of a year-old Alabama paramilitary organization said yesterday.

Tom Posey, founder of Civilian-Military Assistance, said in a telephone interview that he arranged the ill-fated trip for the two volunteers, who joined anti-Sandinista insurgents in Honduras about a week before their deaths. Posey said the victims and other Americans he recruited to aid the rebels were in "no way, form or fashion" connected with the Central Intelligence Agency.

The Reagan administration has also denied that the dead men or their U.S. companions had any connection with U.S. intelligence. In statements to Sen. Daniel Patrick Moynihan (D-N.Y.), the CIA denied involvement and the State Department issued an official denial.

There was no denial that the operations in which the men were involved when they were killed were part of the "secret war" financed by the CIA for more than two years against Nicaragua's Sandinista government.

Congressional sources said the helicopter in which the men were flying when shot down and three fixed-wing planes used in the same military action had been supplied by the CIA.

Various sources, including officials of the Nicaraguan Democratic Force (FDN) being assisted by the two dead Americans, identified the pair as Dana H. Parker, 36, of Huntsville, Ala., a detective with the Huntsville Police Department, and James P. Powell III, also 36, a pilot from Memphis.

Pentagon officials said Parker served part-time as a captain in the Special Forces Group of the Alabama National Guard in Decatur and was an enlisted Marine in Vietnam. Powell's mother, Rose, said in Memphis that Powell owned a fixed-wing airplane and had been an Army helicopter pilot in Vietnam where he was shot down.

Adolfo Calero, the FDN's chief executive officer, said in a telephone interview that Parker, Powell, four other Americans and his brother, Mario Calero, arrived in Honduras Aug. 25 to aid the insurgents.

He said Parker and Powell had been training Nicaraguan exiles at a rebel base on flying a helicopter when the two Americans suddenly announced that they were going on "a rescue mission" and took off with Mario Pozo, a Nicaraguan killed with them.

Mario Calero said last night that Parker and Powell were unarmed when they left on their final flight. He said their helicopter was equipped with rocket pods but no stretchers.

"It wasn't planned," said Posey of the helicopter flight. He insisted that volunteers processed by his organization went to the Nicaraguan border area to train, not fight.

Nicaraguan Defense Minister Humberto Ortega charged that the helicopter had joined three rebel fixed-wing planes in an attack on a government military school at Santa Clara in northern Nicaragua. Ortega said the raid was carried out "with the direct involvement of elements trained by the CIA" and that a civilian worker, 28, and three children had been killed.

Nicaragua last night requested an urgent meeting of the U.N. Security Council to deal with the "situation created by the fresh escalation of aggression." A Nicaraguan spokesman cited the military action Saturday and the downing of a U.S.-made C47 transport plane over Nicaragua last Wednesday as some evidence of the "escalation."

The Americans who accompanied Parker and Powell to Honduras on their recent trip, according to FDN chief Calero, included:

*Cliff Albright of Memphis, a retired Republic Airlines pilot and commander of a paramilitary organization known as Phantom Division, Tennessee Airborne.

The January 1984 edition of Soldier of Fortune magazine said Albright, described as a "master parachute rigger, jumpmaster and instructor with 510 jumps," was part of a three-week Soldier of Fortune mission to El Salvador in August 1983.

*Louis McKnight, who had been an instructor at Hagler Air Service in Memphis. Powell had been a friend of McKnight since high school, according to Powell's mother, Rose.

*Walter (Cisco) Blanton of Sheffield, Ala., who described himself last night as a 10-year veteran of the Special Forces, including the Alabama National Guard.

*A man described only as Bill.

Powell's former wife, Geri, told Washington Post staff writer Fred Barbash that Powell left Aug. 23 for Central America, telling her that "he was going over there to fly supplies and clothes and medicine" and would be back in 10 days.

On Aug. 1, she said, Powell attended a meeting at a Memphis Veterans of Foreign Wars post at which Mario Calero was the main speaker. An advertisement for the meeting said the subject was "the Nicaraguan Democratic Force: FDN, previously sponsored by the CIA and had to function secretly but they are now free to tell the truth." CMA of Decatur, presumably Posey's Civilian-Military Assistance group, was listed among the sponsors.

Previous accounts described Parker and Powell as the first U.S. citizens killed in the "secret war." However, Washington Post special correspondent John Lantigua reported from Managua that the U.S. Embassy there confirmed that Hector Jove Torres, 39, of Arrecino, Puerto Rico, died in combat near the Costa Rican border this spring.

In an interview from his home in Decatur, Posey rejected the widespread description of Parker and Powell as mercenaries. "Those people do not fight for money or train for money," he said of the volunteers, mostly Vietnam veterans, who have signed up through his organization to go to Central America.

Saying that "99 percent of what we do is out of our own pockets," Posey said of the dead Americans, "The only thing they got out of it is some beans and rice."

Posey said he had been visited in April by an FBI agent from Huntsville who asked questions that appeared to be related to the U.S. Neutrality Act.

Posey said he obtained a legal opinion from a local attorney that his organization did not violate this act, which makes it a crime for private citizens to launch an invasion of a foreign country from U.S. shores or for foreign groups to recruit in the United States for military purposes.

Washington Post special correspondent Brian Barger, who conducted research into Posey and his organization this spring, quoted an FBI agent assigned to the Huntsville office as saying "an investigation is pending" on possible Neutrality Act violations.

The agent, who was not named, said in a telephone interview, "We are waiting for word from the Department of Justice for a final determination."

Justice Department sources told staff writer Mary Thornton yesterday that they know of no pending investigation. A department official said the State Department normally would refer such a case to the Justice Department but that no case regarding Posey's group had been forwarded.

Until yesterday, Posey said he had heard nothing from the FBI since April. Asked if he had been informed at any time that there would be no charges, he replied, "Well, I haven't been arrested for anything."

Congress, after repeated clashes divided along largely party lines, has rejected U.S. funding for the Nicaraguan anti-government forces after the current fiscal year, which ends Sept. 30.

Posey said FDN officials told him that their CIA funds were cut off as of June 1 and that U.S.-paid trainers "had to leave." At this point, he said, the FDN said it would welcome American volunteers to train FDN troops along the Honduran-Nicaraguan border.

"Indirectly, you might say it was Congress that killed my two men" because there would have been no reason for them to go if CIA funds had not been cut off, Posey charged.

Moynihan, vice chairman of the Senate Select Committee on Intelligence, rejected this charge, saying that "funds [to support the insurgents] for this period have been appropriated and are still available."

He added, "I hope young Americans will not get the idea that being soldiers of fortune gets you anywhere. They are acting without the approval of the government or the support of the government, and there is a history of getting into lots of trouble."

Correspondent Barger reported that Posey and other CMA officials revealed as early as last May that they had sent three paramilitary training teams to Honduras to train anti-Sandinista rebels there.

"Many of our people are Special Forces-qualified trainers, with years of experience around the world. We teach [the insurgents] the basics -- booby traps, zip guns, bombs, basic survival skills, that sort of thing," Posey was quoted as saying then.

Posey said yesterday that Parker and Powell were part of the first group sent to the FDN by his organization to provide sophisticated training, beyond the "basics."

About 90 percent of those who joined the CMA, he said, are Vietnam veterans like himself who "felt guilt about not winning" and "decided to do something about fighting communism without ropes on us."

Posey said the CMA's aid to anti-Sandinista forces was undertaken after he received a letter last November from Gen. Gustavo Alvarez Martinez, then chief of the Honduran armed forces, welcoming the group's offer of assistance.

Four CMA officials, including Posey, went to Honduras in January carrying supplies for the rebels. They conferred with Alvarez's emissary, Capt. Jorge Belardo Andino, a top official in Honduran military intelligence.

State Department spokesman John Hughes said there had been "no U.S. awareness" of the plan for last Saturday's FDN raid before its initiation. A State Department official told reporters that, because of the congressionally-mandated cutoff of U.S. support, "I think the 'contras' [anti-government Nicaraguan rebels] are raising money and recruiting in all kinds of places."

Referring to the U.S. government role, the official said, "If you don't control the flow of money, you don't have that much influence" on what the rebels do.