BELGRADE, Yugoslavia (AP) _ The interior minister of Kosovo province said Tuesday that authorities have detained 237 ethnic Albanians without charge there and are keeping them in isolation.

Minister Jusuf Karakusi said those held ''are people who acted in the interests of Albanian nationalism and separatism and who .. . exposed their hostile positions,'' according to the state Tanjug news agency.

Mass demonstrations took place in Kosovo in February and March, and clashes between ethnic Albanian rioters and Yugoslav security forces killed at least 25 people, including two policemen.

Ethnic Albanians make up about 85 percent of Kosovo's population of 1.8 million. They were protesting constitutional changes which limited the wide autonomy enjoyed by the province and gave the republic of Serbia a greater say in running Kosovo's affairs.

Yugoslavia is composed of six republics and two autonomous provinces.

A state of emergency was imposed in Kosovo, followed by a crackdown in which more than 800 people were arrested on charges rising from the disturbances.

Karakuski said an additional ''237 have been detained under isolation measures.''

Press reports said that among those jailed without charge are prominent ethnic Albanian politicians, intellectuals and other community leaders who opposed the constitutional amendments.

About 100 people from the central Yugoslav village of Mosevac meanwhile fasted for a fourth day outside the federal parliament in Belgrade on Tuesday to protest alleged harassment by police in their home region.

Another 100 villagers from Mosevac, 180 miles west of Belgrade, were to join the protest, hunger strikers told The Associated Press.

Behind the demonstration is a feud dating to 1986 between the local official youth organization and Communist leaders in the village. The young people accuse the leaders of corruption and political nepotism.

The protest started last Saturday over the arrest of Hasan Delic, a local youth activist, on May 13. Delic has fasted in jail for eight days, press reports said.

Local officials and police were alleged to have misappropriated funds collected for a village community hall.