Turkish Prime Minister Tayyip Erdogan suffers from intestinal cancer.

Biden, who met the Turkish leader for two hours on Saturday, has seen more of Erdoğan than Turks have in public since he underwent keyhole abdominal surgery on Nov. 26.        

"He looked to me good, his stamina was real," Biden told reporters travelling with him aboard Air Force Two from İstanbul to Athens on Sunday .     

"I got the distinct impression that this was something they've nipped in the bud, they've taken care of," he said. "I saw no flagging...I had a very positive impression."     

Biden did not give any details on what Erdoğan may have been suffering from, but added: "He thinks he is going back to work relatively soon."     

Having led Turkey for the past decade, Erdoğan, 57, dominates the political landscape, and all key decisions rest with him, making his absence in recent days more keenly felt.     

Erdoğan will spend a second week recovering at home, an aide told Reuters on Sunday, as the government cancelled a cabinet meeting for a second consecutive week.