Ramush Haradinaj says he is stepping down as Kosovo's prime minister to appear next week in the war crimes court in The Hague as an "ordinary citizen".
Serbian President Aleksandar Vucic called the resignation of Kosovo's prime minister to answer war crime allegations a "trick" that could further delay already bogged-down talks between Belgrade and Pristina.
Ramush Haradinaj on Friday announced he was stepping down as Kosovo's premier to appear next week in the war crimes court in The Hague as an "ordinary citizen".
But Vucic, in a televised address, called that "a political trick by which he wants to gain more popularity, to defeat his political opponents" ahead of early Kosovo elections that could be called for September or October.
He added: "We fear that political development in Kosovo goes toward further delay of the dialogue between Belgrade and Pristina."
Kosovo was a breakaway province of Serbia that waged a 1998-1999 war pitting its Belgrade's forces against its ethnic Albanian population that eventually prevailed with NATO intervention. The territory declared independence 11 years ago.
Serbia refuses to recognise Kosovo's independence, but has agreed to discuss a possible binding agreement on ties with its former province in order to progress on its path to an EU membership.
However EU-mediated dialogue between Belgrade and Pristina has been in stalemate for months, stalled most notably by Kosovo imposing a 100-percent tariff on Serbian goods in November that Haradinaj refused to abolish.
Kosovo President Hashim Thaci could nominate a prime minister in consultation with Haradinaj's ruling coalition to form a new government, but if that fails he must call early elections.
Haradinaj said if that happened he would compete to win a new mandate.
In the meantime, under Kosovo's constitution, the government was performing its regular duties as a technical administration.
Suspect, 'not accused'
Haradinaj, a wartime commander of the Kosovo Liberation Army (KLA), said on Friday he was called to the EU-backed court in The Hague as a suspect for questioning, stressing "I am not accused".
Thaci said several other former KLA officers were also summoned, including his advisor Bislim Zyrapi, wartime KLA's chief of staff.
Former KLA spokesman and former parliamentary speaker Jakup Krasniqi wrote Saturday in a Facebook post that he was one of those also summoned to appear before the special court.
The EU-backed court based in The Hague was set up in 2015 to try war crimes allegedly committed by the ethnic Albanian KLA separatists, notably against Serbs, Romas and Kosovo Albanian political opponents during and after the 1998-1999 war.