The State Department and the U.S. Secret Service expressed concern yesterday that a U.S. Supreme Court ruling this week, upholding demonstrators' rights to protest near foreign embassies, may make it more difficult to provide security for foreign facilities here.

The agencies' statements, issued amid hurried meetings among federal and local law enforcement officials, followed the first disorderly protest since Tuesday's ruling -- a Thursday evening scuffle during a reception at the North Korean ambassador's Northwest Washington home.

There was one arrest there after protesters threw eggs at the car of Secretary of State George P. Shultz.

Officials of the D.C. police department, the U.S. attorney's office, the U.S. Secret Service and the State Department have been meeting to discuss the ruling.

A State Department statement said yesterday that officials are "concerned if the the level of protection presently provided to foreign officials and embassies in Washington is significantly reduced by the ruling."

State Department officials are known to be concerned that other governments might interpret unruly demonstrations outside their embassies here as a U.S. provocation, and that the other governments might retaliate by restricting security to U.S. facilities overseas. Given anti-American sentiment and perilous conditions in some foreign posts, the United States should make special efforts to make foreign officials here comfortable, U.S. officials say.

Assistant D.C. Police Chief Isaac M. Fulwood Jr. said that officials are working to develop standards "so everybody understands how the new policy works . . . . We're trying to strike a balance between the freedom of the American people and the security interests of people who represent foreign governments. We're sensitive to that."

The court ruled 5 to 3 that the First Amendment guarantees protests unless they disrupt "normal embassy activities." Until Tuesday's ruling, D.C. law forbade demonstrators closer than 500 feet to embassies or chanceries.

William Corbett, a Secret Service agent and spokesman, said the decision requires the agency's uniformed officers, who provide security for foreign facilities here, to make split-second decisions that could have international implications.

A Secret Service officer "finds himself with foreign soil behind him and a potentially hostile group in front of him," Corbett said. "There's no buffer zone . . . . The Secret Service doesn't think he's in a very good position."

"The law is being tested now," Corbett said. "Hopefully {officials} will come up with something better."

Fulwood said that losing the 500-foot buffer zone means officers "have got to react faster" to events. That means his department must increase manpower assigned to such demonstrations.

The decision also raises the danger that diplomats inside an embassy might panic and react unpredictably to confrontation, Fulwood said. He mentioned the fatal shooting in 1984 of a British police officer by a Libyan representative from inside Libya's embassy during a rally in London.

Other protests yesterday -- including Baltic people rallying at the Soviet Embassy on 16th Street NW, Iranians at the P Street NW embassy of Iraq and a rally at the New Hampshire Avenue NW embassy of Somalia -- were peaceful.

The Baltic rally took a quirky turn when protesters bearing black wreaths and a letter to Soviet leader Mikhail Gorbachev actually entered the foyer of the embassy building, normally forbidden to protesters. An embassy employee quickly shut the door.

There were no disturbances at other protests in the last three days, including some at the Soviet Embassy by Jews and Armenians. Police officials said that the number of rallies has increased in the last couple of days, and attributed the increase to the court ruling.

In each case, protesters are using the Supreme Court decision for the first time to take their grievances to the gates of the foreign embassies, and to experiment with their new rights, looking over their shoulders at watchful police and Secret Service officers.

The noisy ralliers at the Spring Valley residence of Korean Ambassador Kim Kyung-won were directing their wrath Thursday evening against former Korean president Chun Doo Hwan and the Korean government's suppression of a 1980 uprising in Kwangju, in which at least 200 civilians were killed.

The scuffle broke out when a limousine carrying Shultz and his wife, Helena, was pulling through the metal gates of the compound on Glenbrook Road NW. Angry protesters were only a few feet away, and several threw eggs, rice and other objects. Two eggs hit the limousine's windshield, a State Department official said.

D.C. police said one demonstrator, Hyun Tae Park of Baltimore, threw eggs at the limousine, then eluded the grasp of an officer before removing his shoe, which he also threw. Officers struggled with him briefly, and one officer struck him with a nightstick. The man was arrested for throwing a missile, and then was treated for a slight head wound at Sibley Hospital, police said.

Witnesses said that the 25 or so protesters were extremely emotional, and that after Shultz arrived, police pushed them away from the residence's entrance. "They were real mad, jumping up and down, especially when Shultz came," said one spectator. "I've never seen anything like it."

A government source said the egg-throwing may have been a case of "mistaken identity," with the demonstrators apparently believing that the limousine bore former Korean president Chun, who has been visiting this country. Chun handed power to a former aide, Roh Tae Woo, last month, after Roh's election.

Several other government officials, including Defense Secretary Frank C. Carlucci, attended the large reception.