President Barack Obama has warned the Turkish prime minister that Ankara's position on Israel and Iran could lessen its chances of obtaining US weapons, a report said Monday.
The Turkish leader, Recep Tayyip Erdogan, wants to buy American drone aircraft to attack separatist Kurdish rebels after the US military withdraws from Iraq at the end of 2011, Britain's Financial Times newspaper reported.
The rebel group, the Kurdistan Workers' Party (PKK), has bases in the mountains in the north of Iraq, near the Turkish border.
"The president has said to Erdogan that some of the actions that Turkey has taken have caused questions to be raised on the Hill (Congress)," a senior administration official was quoted as saying in the daily paper.
These questions centred on "whether we can have confidence in Turkey as an ally," said the official.
"That means that some of the requests Turkey has made of us, for example in providing some of the weaponry that it would like to fight the PKK, will be harder for us to move through Congress."
The United States voiced disappointment after Turkey voted against fresh UN sanctions on Iran, which the United Nations Security Council adopted in June.
Ankara argued that Tehran should be given a chance to carry out a nuclear fuel swap deal, brokered by Turkey and Brazil.
Relations between Turkey and Israel were thrown into crisis after an Israeli raid targeting Gaza-bound aid ships on May 31 that left nine Turks dead.
Obama called on Turkey to cool its rhetoric about the raid when he met Erdogan at the G20 summit in Toronto in June, said the FT.