PANAMA CITY, Panama--The government of Gen. Manuel Antonio Noriega declared a national "state of urgency" yesterday that allows it to suspend individual freedoms.

A decree said the action was taken because of "a real situation of undeclared war against the republic of Panama" by the United States and domestic political opponents.

In other developments yesterday:

.Angry dock workers moved huge blockades across the entrance to their port near the Panama Canal to fight off an army takeover by troops loyal to Noriega.

.Noriega fired his intelligence chief and four other officers in an apparent purge of his fractured Defense Forces two days after a failed coup attempt against the military strongman.

.Four American military police officers were arrested in the capital by Panamanian authorities and held for several hours, the Pentagon said yesterday. The Panamanian newspaper Critica said the Americans were carrying handguns, maps of the capital and "military implements" when they were detained in an area "where daily activities disturbing the public order" had occurred.

The government's "state of urgency decree did not specify what measures would be taken and said only that "the executive branch will adopt the measures adequate for the preservation of public order to repell the domestic and foreign attacks on the national economy and to face the state of urgency throughout the country."

It said that for the past several weeks, "Panama has been the object of an attack on its economy by the United States of America in coordination with national political sectors desperate to take over the government by force."

The situation, it said, affects the "structure of national life."

The decree was based on Article 51 of the Panamanian Constitution which gives the government the power to suspend rights and liberties in cases of war or disturbances affecting public order.

The United States has applied economic pressure, including blocking the transfer of currency to Panama and witholding Panama Canal fees, in an attempt to encourage the ouster of Noriega.

Panamanians, without cash for weeks, lined up at public parks and pay stations yesterday to receive bags of food being doled out by the government.

Noriega gave no reason for yesterday's military ousters.

Col. Bernardo Barrera had been in charge of intelligence for the 15,000-member Defense Forces, which includes Panama's army, navy, police and air force.

A source close to the Defense Forces said Barrera might have been faulted for not knowing in advance of Wednesday's coup attempt, which was said to have involved a few junior officers lead by the nation's police chief, Col. Leonidas Macias.

At the Balboa Port, about a mile outside the Panama Canal, about 300 striking dock workers moved carsized containers across the port entrance to fight off an army takeover ordered Thursday by the government.

"The port is shut down," said one dock worker. "We won't accept anything less than what they owe us," he said, asking not to be identified for fear of reprisal. "We'll wait here for [the army]."

Four shipping containers were stacked across the port entrance. They formed a barricade nearly 20 feet high and no yehicles or machinery were passing in or out.

Ports at Panama City and Colon, used primarily to receive and ship cargo, closed earlier in the week when dock workers angry about not being paid went on strike. The Panama Canal Commission said the shutdowns had no effect on its operations.

The four American military police arrested Thursday night in Panama City were identified by the Critica newspaper as Danny H. Feltro, William Jerry, Virts Richard and Tammy Markley.

The newspaper did not provide their ranks or other information, and the Pentagon said yesterday it could not immediately confirm the identities printed by the paper.

A U.S. Southern Command statement in Panama City said the four were members of a military police detachment checking on the "security of dependent families" living in the area in which they were detained.

The U.S. military dependents, like everyone else in Panama, have been without lights and water for extended periods because of the recent strikes.