BRUSSELS - Belgian Foreign Minister Louis Michel said on Sunday it would be "unthinkable" to allow Turkey to join the European Union if Ankara defied U.S. and NATO leaders and sent its forces into northern Iraq.

Turkey's government on Saturday denied media reports that it had sent more than 1,500 troops into the Kurdish-controlled area. NATO has accepted the assurances.

Ankara is concerned that Iraqi Kurds might use the U.S.-led war against Iraq as an opportunity to establish a separate Kurdish state, and fear such a state would reignite the armed Kurdish separatism in southeastern Turkey that cost 30,000 lives in the 1980's and 1990s

Michel, speaking in a televised debate, said he would be involved in a diplomatic effort to exert "very strong" pressure on Ankara not to send Turkish troops over its border with Iraq.

"I think that would be the determining element for refusing them accession to Europe," he said. "It is unthinkable for Turkey to join Europe if they enter Kurdistan."

Reports of a Turkish incursion sparked a quick reaction from NATO member Germany, which said it would withdraw its crews from the alliance's AWACS surveillance planes patrolling Turkish airspace if Ankara became a belligerent force in northern Iraq.

Turkey and the United States, both NATO members, are at odds not only over Turkey's wish to send troops into northern Iraq but also over its refusal to allow U.S. troops to launch an attack on Iraq from Turkish soil.

Washington fears confrontation between Turkish troops and Kurdish groups that could seriously disrupt the U.S. military campaign in Iraq and have wider consequences for subsequent efforts to draw a fragmented country together.

Failure of talks to unite the divided island of Cyprus has already hurt Turkey's bid to join the EU. Ankara won a pledge in December that the EU would open entry negotiations if a December 2004 summit agreed it had met political and economic criteria.