President Reagan on Friday invoked a sweeping economic-sanctions law against Panama in a renewed effort to force military strongman Manuel Antonio Noriega to surrender his hold on the Central American country.

"I have authorized these steps in response to the unusual and extraordinary threat posed by" Noriega, Reagan said in a letter to congressional leaders.Reagan's move, which had been hinted earlier by a senior administration official, came as the United States continued to elect mostly economic options in response to Noriega's unflinching hold on power.

White House spokesman Marlin Fitzwater said that among the steps the president ordered under provisions of the International Emergency Economic Powers Act are:

Blocking assets of the government of Panama in the United States.

Prohibiting payments by all people and organizations in the United States to the Noriega regime.

Prohibiting payments to the Noriega regime by all U.S. citizens and organizations in Panama,

including U.S. branches and subsidiaries.

"These further steps reaffirm our commitment to democratic government in Panama and our belief that Noriega would best serve his country by complying with the instruction of President (Eric Arturo) Delvalle to relinquish his post," Reagan said in the letter to Capitol Hill leaders.

The official, describing the presidential decision-making process for reporters with the proviso of anonymity, had said earlier that invocation of the International Emergency Economic Powers Act was one of the options that has been presented to Reagan by his advisers.

It was the first time the law has been invoked since the administration used it in the mid-1980s to squeeze Libyan strongman Moammar Gadhafi. Then-President Carter invoked the act against Iran in the late 1970s.

White House chief of staff Howard Baker, talking to reporters as the president vacationed at his mountaintop ranch, denied that the economic sanctions used so far have failed.

"After all, General Noriega is (a) much-beleaguered, de facto leader of the Panamanian government," he said. " . . . But I think that there has been a remarkable success so far in the economic efforts by the United States to convince General Noriega that he should leave."

The United States, in the wake of Noriega's ouster of Delvalle in late February, slapped several sanctions against Panama. These included freezing that country's assets in the United States and withholding millions of dollars in payments the United States makes to the Panama Canal Commission.

But the administration apparently has been frustrated with a lack of cooperation from U.S. businesses with operations in Panama. Invoking the emergency economic powers law would allow the government to forcibly withhold tax payments that American businesses make to the Panamanian government.

Administration officials have been studying the ramifications of using the emergency act for some time.