The National Congress, in an action that openly challenged the authority of President Roberto Suazo Cordova and thrust this country's politics into turmoil, voted today to restructure the Supreme Court.

Suazo Cordova issued a statement saying the legislature's move was unconstitutional and calling it "a technical coup."

The president's top aide, Minister of the Presidency Ubodoro Arriaga, said that the government might declare martial law if "a crisis becomes acute."

In an indication that the armed forces were siding with the president, military police arrested Ramon Valladares, who was named by the Congress as the new head of the court, Honduran radio and press reports said. But the armed forces were widely reported to wish to avoid intervening.

"We cannot involve ourselves in the politics of the country," a senior armed forces officer said.

[A military spokesman told The Associated Press, however, that Suazo Cordova had ordered the arrests of all five new justices, and that the head of the armed forces, Gen. Walter Lopez, "is willing to carry it out.]"

The standoff between president and legislature represented a serious disruption in the politics and government of this pivotal U.S. ally in Central America, according to Honduran politicians and foreign diplomats. It appeared to mark a setback, although possibly only a temporary one, for Washington's efforts to promote consolidation of what U.S. officials have described as Honduras' fragile democracy.

"This is what we get for encouraging pluralism here," a U.S. source said.

Honduras effectively had two supreme courts following the congressional vote: the old one loyal to the president, and a new one including the five judges chosen by the Congress to replace the five whom it voted to unseat. The court has nine members.

In response, the president ordered the Treasury Ministry not to pay salaries to the newly named judges. He stationed small squads of riot police, which are under the armed forces' command, outside the court's offices and the Congress.

The confrontation brought to climax a long brewing dispute between the president and dissident leaders of his own Liberal Party. Political leaders on both sides said that dissident Liberal factions were using the Supreme Court issue as a way of pressuring the president in an internal party fight.

The Liberal dissidents are angry at Suazo Cordova because he has sought to guarantee that he pick the Liberal candidate to succeed him as president in elections scheduled for Nov. 24, politicians and diplomats said. Dissatisfaction with maneuvering by Suazo Cordova, who is barred by law from succeeding himself, has risen steadily in recent months, they said.

In particular, the president has opposed the candidacies of Liberal leaders Efrain Bu Giron, who is president of the Congress, and of Jose Azcona.

Their factions of the Liberal Party combined with deputies of the opposition National Party to name the new judges. The vote, held shortly after midnight, was 50 to 29, with three abstentions.

In a statement broadcast on radio and television, Suazo Cordova urged citizens to remain "tranquil and serene" and condemned "grave acts of violation of the constitution of the republic, motivated by deputies acting out of desperate personal ambitions who ignore the higher interests of the country."

Opinions differed as to whether the three-year-old constitution permitted the Congress by itself to replace Supreme Court judges. The Congress names the judges to four-year terms, but the constitution does not specifically empower the legislature to remove them.

The court is directly involved in the Liberal Party's internal affairs because the president of the court is a member of another government body, the Electoral Tribunal, which rules on party disputes.

Carlos Arita, the court president loyal to Suazo Cordova, consistently has voted in the tribunal against the president's political rivals. Arita was one of the judges whom the Congress voted to replace. Despite the indications of military backing for the president, politicans and diplomats said that the officer corps preferred to avoid taking sides and to let the politicians sort out their troubles.