Poland has threatened to derail Thursday's EU summit as it attempts to block the re-election of Donald Tusk as president of the European Council, BBC reports. 

Foreign Minister Witold Waszczykowski said Poland would "do everything" to prevent a vote on the matter.

The ruling Law and Justice Party (PiS) implacably opposes Mr Tusk, a former prime minister from a rival party.

Correspondents say such hostility among compatriots is highly unusual in EU politics.

But Mr Tusk is still expected to get enough support to keep his post.

German Chancellor Angela Merkel has backed a new 30-month term for Mr Tusk, saying it would be a "sign of stability".