Turkish Prime Minister Tayyip Erdogan has acknowledged his relations with U.S. President Barack Obama have soured, saying he had been disappointed among other things by a lack of U.S. action over the war in neighboring Syria.
Erdogan enjoys strong support in Turkey and is expected to become Turkey's first directly elected president in a vote on Aug. 10, but his leadership has left Turkey increasingly isolated on the global stage.
Everything from his bombastic rhetoric on Israel to his crackdown on anti-government protests last summer has raised concern among Western allies.
Asked in a televised interview late on Monday whether relations with Obama had become strained, Erdogan said he no longer spoke directly to Obama as he did in the past.
"Naturally because I did not get the results I wanted in this process, in particular on Syria, our foreign ministers hold talks, as I do with (U.S. Vice President Joe) Biden," he said.
"Currently, to be honest, we discuss the Iraq issue with Biden. I said to our president, you call and speak to Mr. Obama directly about this subject," Erdogan said, adding he was not sure whether the two men had since done so.
Turkey has been an opponent of Syrian President Bashar al-Assad, backing rebels fighting to oust him and allowing the political opposition to organise on Turkish soil. It long lobbied for international intervention in the war.
Erdogan has also been a fierce critic of Israel's offensive into Gaza, accusing the Jewish state of terrorising the region and likening a member of the governing coalition to Hitler, words which drew a sharp rebuke from Washington.
He was also a strong critic of the Egyptian military's toppling last July of Islamist President Mohamed Mursi, saying the West and Arab nations had failed to condemn his overthrow.
Erdogan's chief adviser Yalcin Akdogan on Tuesday described the Israeli government as "mentally ill" and accused Washington of having a "cross-eyed view" of the world.
"Nobody has the right to be insolent towards the prime minister. Those who just cast out comments left and right should first worry about their own respectability," Akdogan said of the U.S. criticism of Erdogan's rhetoric.
"The West lost its democratic face in Egypt, its humane one in Syria, its sincere one in Iraq and its peaceful one in Palestine. Who should believe their lies now," he wrote on his Twitter account.
Erdogan's indomitable rise, likely to be crowned next month with the presidency he has long coveted, has drawn concern in parts of Washington and the European Union, which Turkey has long sought to join.