A group of Croatian nationalists claimed "full responsibility" yesterday for a Tuesday morning bombing at the Northwest Washington home of the Yugoslav charge d'affaires.

In a two-page typewritten letter mailed to The Washington Post and other news media, the group, "Croatian Freedom Fighters," said it carried out the "action in Washington, D.C. as a sign of protest against the Yugoslav government" and its treatment of the Croatian movement's supporters. The letter, postmarked Tuesday, was in Croatian.

There were no injuries in the 4 a.m., explosion at the home of acting Yugoslav ambassador Vladimir Sindjelic on Quincy Street NW.

The FBI has been investigating "the possibility that the bomb was planted by one of the anticommunist Yugoslavian terrorist splinter groups" that have claimed credit for previous acts of violence, an FBI spokesman said shortly after the blast.

Yesterday's letter appeared to come from one such group.

The letter demanded, among other things, an "urgent investigation into the case of Miro Baresic" and that a Swedish doctor be allowed to visit Baresic in a Swedish prison.

Baresic, a 29-year-old karate expert who was released from a Swedish prison in 1972 as part of a ransom demand by Croatians who hijacked an airliner, worked for the Paraguayan embassy in Washington in 1977 and 1978 under a different name.

Later he became a target of a major federal investigation into acts of terriorism by right-wing Croatian separatists against Yugoslavs in the United States and elsewhere. Baresic went to Paraguay in 1978. Later he and another Croatian terrorist there was extradited to the United States, and spent about a year in a New York jail before being deported to Sweden last month.

"We are turning attention of the American and world public and governments to the decision of the command of Croatian liberation forces that actions toward Croatian fighters and nationalists will no longer be tolerated . . .," the letter said.

The group said it would continue to make its demands "until the creation of a Croatian state."

Since 1971, when the Yugoslav region called Croatia lost some of its autonomy, there have been a number of attacks against Yugoslav government personnel and installations abroad.

Croatian terrorists were implicated or claimed involvement in a series of assassination attempts in various countries, ranging from West Germany to Paraguay, in the first half of the decade. In 1972 they claimed responsibility for blowing up a Yugoslav airliner over Czechoslovakia, a blast in which 29 persons were killed.

In April 1971, Baresic himself pleaded quilty in Sweden to the assassination of the Yugoslav ambassador to Sweden earlier that year.

Croatian nationalists also hijacked an American jetliner bound for Paris in 1976. During that incident a New York City policeman was killed when he tried to disarm a bomb planted in Grand Central Station by Croatians in connection with the hijacking.

A New York City police report earlier this year listed 60 "significant" acts of terrorism by Croatians worldwide since 1962. At least 50 persons have died in such incidents since 1972, the report said.

One State Department official has theorized that the bombing of Sindjelic's home here was "an attempt to throw a shadow" on President Carter's scheduled trip to Yugoslavia next month. Carter is scheduled to visit the country -- to underscore continuing U.S. support for Yugoslav independence following the death of President Tito -- on the way to a meeting of the North Atlantic Treaty Organization in Turkey.

President Tito died May 4 after a long illness, and was replaced by a new collective government.

The State Department official said the agency had warned Sindjelic and other Yugoslav diplomats about possible targets to their safety because of a State Department fear that Tito's death might prompt an outbreak of anti-Yugoslav government violence.