A 10-day sit-in and hunger strike by 26 Chileans inside a U.N. office here ended today after the United Nations announced that the Chilean government would provide information on strikers' relatives who are alleged to have disappeared after arrest by security police.

Conversations with Chilean representatives about the terms of the settlement were carried on in New York by U.N. Secretary General Kurt Waldheim and in Santiago by Enrique Iglesias, director of the U.N. Economic Commission for Latin America, after "close consultations" with the U.S. and other embassies and Chilean humanitarian institutions, according to informed sources.

It was the first time the government acceded to demands by persons inside Chile who claim that their relatives have been victims of the security police. The 10-day sit-in was also the first public protest inside Chile about human-rights issues since the military took power in 1973.

Human-rights advocates here said, however, that they fear that the information provided by the government may be useless in locating the missing persons. In replies to the U.N. Human Rights Commission, Chile has said that the missing persons were "legally dead" or non-existent or had been killed in guerrilla activity outside the country.

The hunger strike and sympathy sit-ins in Washington, Stockholm and elsewhere received scant attention in the pro-government Chilean media.

The settlement came one day after the Chilean government declared that it had "closed . . . all claims or analysis" relating to the release of prisoners and the identification of "subversives."

The statement said, "At present there is no one in Chile imprisoned or under arest because of subversive crime or for merely political reasons, as some intentionally call it."

The man the government called its last political prisoner, Jorge Montes, was freed over the weekend in exchange for 11 East German prisoners. Montes was the last prisoner pailed under the state-of-siege law imposed after the coup, but many others are in jail or "internal exile" after being tried by military tribunals.

A diplomatic source said the Chilean government knew of the concern among U.S. and other embassies and was "deeply aware of the international embarrassment" caused by the sit-in.

The protesters demanded that a commission of Chileans and people of other nationalities be named to investigate the disappearances of about 500 people named on lists compiled by the Catholic Church. The 500 names represent the best-documented cases of about a thousand people said to have disappeared since the coup.

A statement released at U.N. headquarters in New York said the Chilean government "is prepared to give information on the whereabouts of relatives of the group of 26." It did not mention the list of 500 missing persons. The statement added that no sanctions will be applied to the strikers, who indicated that they intend to remain in Chile.

A United Nations official here said Waldheim assumed a very active role in negotiations to end the sit-in since it began June 14. The official said the 26 Chileans began the sit-in after having exhausted all legal channels to locate their relatives.

"They looked to the United Nations and to the United Nations declaration on human rights as a last resort for help," he said.

[Five Americans who had been fasting since June 14 at the office of the U.N. Economic Commission for Latin America, 1801 K St. NW, ended their vigil after learning that the sit-in in Santiago had ended. A priest, a nun and three members of the Community for Creative Non-Violence, were applauded when they emerged from the office.]