Former Kosovo Prime Minister Agim Ceku, who is wanted in Serbia on war crimes charges, was arrested in Bulgaria, the interior ministry said.

"Agim Ceku was arrested at Geshevo when he entered Bulgaria following an Interpol red notice," or an international arrest warrant, spokesman Diana Yankulova said. A Bulgarian court will look into his case in coming days, she added.

In the Kosovo capital Pristina, an official of Ceku's Social Democrat Kosovo party confirmed the arrest.

"Mr Ceku was detained at the Qustendil border crossing between Bulgaria and Macedonia at 5.30 p.m. following an arrest warrant issued by Serbia on May 9," according to party spokesman Gezim Kasapolli.

Mr Ceku "was in Bulgaria to hold talks with (Bulgaria's) deputy foreign minister and other people," he added.

Talks are underway to free Mr Ceku, he said. "We expect him to be freed early in the morning."

Mr Ceku, 48, is wanted for war crimes allegedly committed during the 1998-1999 war in then Serbian-ruled Kosovo when he was military chief of the Kosovo Liberation Army, made up of ethnic Albanian guerrillas. Serbia says he also committed war crimes in Croatia during the former Yugoslav republic's 1991-1995 war of independence. He also has Croatian citizenship.