Cameron pressing to conclude EU talks in December - newspaper

LONDON (Reuters) - Prime Minister David Cameron is pressing other members of the European Union to conclude talks on Britain's ties with the 28-member bloc at a summit in two weeks' time, European Council President Donald Tusk was reported as saying.

Tusk told the Guardian newspaper he agreed with Cameron's drive to finish his renegotiation before Christmas and would help the British prime minister, who has promised to hold a referendum on Britain's EU membership by the end of 2017.

EU officials have said that, while the British reform demands would be on the agenda of the next European Council session Dec. 17-18, it would be difficult to reach a final deal.

Some of Cameron's demands, such as curbing EU migrants' access to Britain's welfare system, are seen as a challenge to the EU principle of non-discrimination.

"In fact, his personal opinion and mine were and are that December is better than February," Tusk told the Guardian, referring to the next two EU summits.

"If he is ready to take this risk, I will be helpful. But then, it would be his risk ... If Cameron is sure December is better for him as the organiser of this referendum, I will be helpful and I am ready to convince our officials."

Tusk must decide in days on whether to put a final UK ultimatum on the agenda for the summit, the Guardian said.

EU officials said last month that the bloc's leaders were not only unlikely to reach a deal next month with Britain on its demands for EU reform but might not even narrow differences at a pre-Christmas summit.

Tusk also told the Guardian that his instinct was to give the negotiations more time until February, although he "understood [Cameron’s argument] that in fact maybe we have to play against time".

(Reporting by Elizabeth Piper; Editing by Mark Heinrich)