Polish PM Tusk resigns to take European Council role
Polish Prime Minister Donald Tusk says he has submitted his resignation in order to take up his new role as European Council president in December.
President Bronislaw Komorowski is expected to accept it on Thursday.
Under Poland's constitution the whole of the cabinet has to resign alongside Prime Minister Tusk.
Mr Komorowski and the governing coalition are supporting the current parliamentary speaker, Ewa Kopacz, as the new prime minister.
The BBC's correspondent in Warsaw, Adam Easton, says the new PM and cabinet require parliamentary approval.
But this should not be an obstacle because the coalition has a small majority, he adds.
Mr Tusk, who has been Polish leader since 2007, told reporters in Warsaw: "I've handed over my papers."
He is the only Polish prime minister to have been re-elected since the collapse of communism in 1989.