Greek prime minister Alexis Tsipras says he does not want early elections but rebels within his radical left Syriza party could force his hand.

Mr Tsipras said that if he loses his parliamentary majority, which has been challenged by party hardliners who oppose Greece's talks for a new international bailout, he will have to call national elections.

He told Syriza's Sto Kokkino radio station that he wants to hold a party congress in September, once the vital bailout deal is sealed, to decide on the party's future.

Mr Tsipras' six-month-old government is negotiating the terms of the €85 billion bailout - Greece's third in little more than five years - with representatives of the country's international creditors. The deal must be concluded before August 20.