Deputy PM held by Yugoslav police

Peresic in a 1998 photo

BELGRADE, Yugoslavia (CNN) -- A Serbian deputy prime minister, who served as Yugoslav army chief of staff under Slobodan Milosevic, has been detained by police.

The development was confirmed by Deputy Prime Minister Momcilo Perisic's office. It is not known why Perisic was detained by the Yugoslav military police or if any charges have been filed.

A U.S. diplomat has also been detained in Belgrade although no one has officially linked the two incidents.

Perisic, who was Yugoslavia's chief of staff during the wars in Croatia and Bosnia, had been sacked by Milosevic in 1998 before the NATO air war against Yugoslavia.

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Perisic had been critical of Milosevic's campaign against ethnic Albanian militants.

A Perisic spokesman could not confirm media reports that Perisic had been arrested on suspicion of passing secret documents to a U.S. diplomat.

Also in Belgrade, the U.S. embassy confirmed that an embassy official, who was not identified, was detained by police on Thursday night and held for up to 15 hours.

He had been detained in a Belgrade restaurant, where apparently he met with a high-ranking Serb government official.

U.S. embassy spokesman Paul Denig said the embassy would lodge a formal protest over the detention.

After being sacked by Milosevic, Perisic founded his own party, the Movement for Democratic Serbia, joined the coalition that toppled Milosevic in 2000 and in January 2001 became a deputy prime minister in the Serbian government.

Croatia has indicted Perisic for war crimes and tried him in absentia for shelling the Adriatic city of Zadar, where he was a Yugoslav army commander in 1991 at the start of the Croatian war.

He was found guilty and sentenced to 20 years in prison in 1996. Croatia wants him removed from office.

The U.N. war crimes court in The Hague has not published any charges against Perisic.