WASHINGTON -LRB- CNN -RRB- -- American U2 reconnaissance planes have been flying over the Turkey-Iraq border to observe military movements , said three U.S. military sources Wednesday . A Turkish army convoy heads toward the Turkey-Iraq border on Monday . Word of the flights comes a day before top-level meetings between U.S. and Turkish government officials and prior to a regional conference aimed at easing tensions between Ankara and Kurdish rebels across Turkey 's border with Iraq . Turkey -- which shares its Incirlik air base with U.S. forces -- is a key member of NATO and acts as a vital conduit for U.S. military supplies . Pentagon spokesman Geoff Morrell confirmed Wednesday that U.S. military and intelligence communities are sharing information with Turkey to help them fight members of the Kurdistan Workers ' Party , or PKK , who have made cross-border attacks . See location of key U.S.-Turkish air base '' `` We are assisting by supplying them , the Turks , with intelligence , lots of intelligence , '' said Morrell . `` There has been an increased level '' of intelligence sharing . Turkey has urged Washington to offer more support against the rebels and Ankara has threatened to launch a full-scale offensive if Iraqi and Kurdish officials fail to neutralize the PKK . U.S. and Iraqi diplomats have been working to restrain Turkey from such a response . Recent limited fighting in southeastern Turkey has spilled into northern Iraq . During operations near the border on Monday , Turkish forces fired on suspected rebel positions . Watch Turkish helicopters fire on rebels '' On Thursday , U.S. Secretary of State Condoleezza Rice is set to meet with Turkish officials in Ankara and President Bush holds talks in Washington with Turkish Prime Minister Recep Tayyip Erdogan . Also , a conference of regional officials , including Iraq , is scheduled Thursday and Friday in Istanbul . Iranian Foreign Minister Manouchehr Mottaki has joined efforts to ease cross-border tensions . Mottaki met in Iraq Wednesday with his Iraqi counterpart , Hoshyar Zebari , and Iraqi Prime Minister Nuri al-Maliki . Mottaki 's involvement prompted him to delay a scheduled visit to Lebanon , according to Iran 's Islamic Republic News Agency , which quoted Iranian Ambassador to Lebanon Mohammad Reza Sheibani . Iran 's foreign minister is offering his `` full support '' to the regional conference in Istanbul , said a statement from al-Maliki 's office . The statement also said Mottaki wants to help `` solve the border crisis between Turkey and the PKK . '' Earlier this month , proposed legislation in the U.S. Congress prompted Turkey to threaten to restrict U.S. access to Turkish airspace or cut off access to the air base at Incirlik . Some lawmakers wanted a vote on legislation that would have officially declared that the killing of Armenians by Ottoman Turks in World War I was `` genocide . '' Turkey recalled its ambassador to the United States and warned of repercussions in the growing dispute . Sponsors of the congressional resolution have asked for a delay in the vote . E-mail to a friend