PANAMA CITY, FEB. 26 -- Panama's military-dominated legislature today named an ally of strongman Manuel Antonio Noriega as acting president after voting to depose the country's titular head of state, Eric Arturo Delvalle.

In a move seen by the opposition here as a de facto military coup, Delvalle was ousted hours after announcing yesterday that he was firing Noriega as commander of the Panama Defense Forces.

Noriega, who was indicted earlier this month by two federal grand juries in Florida on drug-trafficking and racketeering charges, refused to accept his dismissal, and senior officers of the 15,000-member Defense Forces rallied to his support.

In a predawn emergency session boycotted by opposition parties, 38 of the 67 members of the National Assembly approved the appointment of Education Minister Manuel Solis Palma as "minister in charge of the presidency," and he was promptly sworn in.

Delvalle, however, refused to accept his ouster.

"I am the president of Panama this morning," he told reporters. "There is no legal power in Panamanian laws or the constitution that allows the National Assembly" to depose a president.

In Washington, the Reagan administration said it continues to recognize Delvalle as president of Panama and began a diplomatic campaign against Noriega. President Reagan rejected any U.S. military action to force Noriega out {Details, Page A17}.

Appearing calm as he received visitors at his home, Delvalle, 51, called for an international trade embargo against his country to demonstrate rejection of the military-dominated government. But he indicated he did not favor any U.S. military intervention. Tonight, Delvalle called for "national resistance to paralyze the entire country starting Monday," The Associated Press reported.

Gen. Noriega, who has wielded the real power in this country of 2.3 million people since he took command of the Defense Forces in 1983, declared in a radio interview that the United States has been using "psychological warfare" and "slander" against him.

He charged that the Reagan administration was behind Delvalle's abortive move to dismiss him, but he said U.S. interests here would not be harmed. Delvalle, he said, was staying home with his family "without any problem."

After the National Assembly session early today, Noriega, wearing a camouflage uniform and a red and black cap, appeared at the Legislative Palace with members of his general staff to congratulate Solis Palma. He called Delvalle's move against him "treachery" and said it resulted from "confusion and pressure."

Noriega addressed several hundred supporters in a downtown plaza this afternoon and led them on a march to the Presidential Palace for a public appearance with Solis Palma. The two embraced and laughed together, clasping each other's upraised hands before the crowd.

Panamanians appeared to react with calm resignation to the events. There were no reports of significant antigovernment demonstrations today, and activity in Panama City appeared normal.

The military acted swiftly last night to stifle any dissent, closing the major opposition newspaper, La Prensa, a television station owned by Delvalle and the offices of two opposition groups: the Christian Democratic Party and the National Civic Crusade.

Christian Democratic Party President Ricardo Arias Calderon last night was denied reentry into Panama from a trip abroad. He said he was seized at the airport by security men and forcibly put on a plane to Costa Rica, an action that he said violated Panamanian law.

Leaders of the National Civic Crusade, a business and professional group, said tonight they would organize an escalating series of strikes in an effort to bring Noriega down. They also said they were calling on supporters to remain calm and avoid violence. A Civic Crusade leader, Eduardo Vallarino, called the move against Delvalle "a coup d'etat" and said that because of it, the government "has lost whatever international support it had."

{Calderon said in Costa Rica today that his country had become "ungovernable," special correspondent Jake Dyer reported from San Jose. Calderon rejected any U.S. military intervention in Panama, saying, "We have to attend to our own problems."}

The events yesterday and today served to erode further the constitutional facade of the Panamanian government, which long has been dominated by military strongmen.

Only Nicaragua's Sandinista government immediately recognized Solis Palma's new government, although Cuba's ruling Communist Party also expressed support for Solis Palma and Noriega.

{Nicaraguan President Daniel Ortega, in an afternoon speech, offered Noriega "all the solidarity of the combative people of Nicaragua," correspondent Julia Preston reported from Managua. Ortega called Noriega by phone Thursday night to express Nicaragua's broad endorsement, the Sandinista daily Barricada reported today.

{Ortega said his government is willing to defend its friends "no matter how isolated and alone they may be." He blamed Noriega's troubles on his alleged refusal to assist a U.S. military invasion of Nicaragua.}

{The Latin American "Group of Eight" immediately suspended Panama's participation in a foreign ministers' meeting in Colombia, Reuter reported. The foreign ministers of Brazil, Argentina, Uruguay, Peru, Colombia, Venezuela and Mexico announced that Panama would remain suspended until it was clear that democratic institutions remained in force in the country.}

Delvalle, long considered a Noriega puppet, abruptly announced on national television yesterday that he was exercising his constitutional power to remove Noriega as Defense Forces commander. As a replacement, he named the military chief of staff, Col. Marcos Justines, who then announced his refusal to accept the post.

Justines and other officers on the general staff rallied around Noriega, and the military began rounding up legislators loyal to him for the emergency session, which began shortly after 1 a.m.

The assembly passed a resolution deposing Delvalle on grounds that his dismissal of Noriega was unconstitutional and that Delvalle was acting "to permit the intervention of the U.S. government in the internal affairs of Panama," thereby endangering national sovereignty, peace and security in the country. The assembly also voted to depose Vice President Roderick Esquivel, who had been evicted from his office by the military in September after he called for Noriega's removal.

In a speech after he was sworn in as the acting president, Solis Palma accused the United States of having instigated an "institutional crisis" in Panama and said the country would follow "a policy of nonalignment."

But he called on the United States to maintain normal commercial and diplomatic relations with Panama, and he pledged that the security of U.S. citizens and their property would be guaranteed, along with foreign and domestic business and banking interests.

Solis Palma, 70, joined the government as education minister in 1984 after having been aligned for years with the opposition to military rule. His switch of allegiance has never been publicly explained.

THE AMERICAN PRESENCE

Panama is home to the U.S. Southern Command, responsible for all U.S. military activities in Latin America south of Mexico. The Southern Command is composed of:

ARMY

193rd Infantry (Light) Brigade: Provides ground defense of the canal. Operates U.S. Army Security Assistance Agency for Latin America. Supports regional missions including humanitarian assistance and emergency evacuations.

Military Police: Provide security. 3rd Battalion 7th Special Forces Group: Airborne unit of special operations forces.

AIR FORCE

U.S. Air Force Southern Division: Provides air defense of canal area, tactical air support for U.S. forces, search and rescue. Assists Inter-American Air Forces Academy in providing technical training for airmen and professional education for air force officers throughout Latin America.

NAVY/MARINES

U.S. Naval Forces Southern Command: Maintains harbor patrol unit of nine boats. Provides fleet support for the transit of U.S. and other naval units through the canal. Coordinates plans for naval forces assigned for contingency operations. Monitors operation of U.S. Naval Small Craft Instruction and Technical Training School.

THE U.S. MILITARY POPULATION

Army: 6,900

Air Force: 2,300

Navy/Marines: 600

Military dependents: 13,000

Defense department civilians: 5,800

PANAMA AT A GLANCE

Population: 2,275,000 (1987)

Geography: 29,208 square miles, slightly larger than West Virginia.

Government: Gen. Manuel Antonio Noriega, now under investigation for drug trafficking, helped oust Panama's elected leader in 1985 and elevated Eric Arturo Delvalle to the figurehead presidency. Delvalle dismissed strongman Noriega as head of the country's Defense Forces Thursday, but the National Assembly voted early yesterday to oust Delvalle.

History: Panama declared independence from Colombia in 1903, with the support of the United States. Two weeks later the United States purchased rights to build the Panama Canal, which was opened in 1914. Treaties implemented in 1979 abolished the "Canal Zone" and placed the waterway under the authority of a commission on which the United States maintains majority representation until 1989. According to the treaty, U.S. forces will remain in Panama until the year 2000 and the neutrality of the canal is guaranteed.

SOURCE: Bureau of the Census, Europa Yearbook