Geert Vanden Wijngaert, Associated Press
German Chancellor Angela Merkel, second right, speaks with, from left, Finnish Prime Minister Alexander Stubb, Dutch Prime Minister Mark Rutte and Bulgarian President Rosen Plevneliev during a round table meeting at an EU summit in Brussels on Friday, Oct. 24, 2014. Britain says its prime minister, David Cameron, is protesting a European Union request for an additional 2.1 billion euro ($2.65 billion) contribution to the EU coffers at a time of increasing pressure at home for the country to leave the bloc.

BRUSSELS — Britain is protesting a European Union request for an additional 2.1 billion euro ($2.65 billion) contribution to the EU coffers at a time of increasing pressure at home for the country to leave the bloc.

British officials on Friday confirmed a report in the Financial Times that their nation had been asked to top up its contribution by some 20 percent. They spoke on condition of anonymity because talks on the matter were ongoing.

The Netherlands too has been asked for a big top-up, of 642 million euros, which Finance Minister Jeroen Dijsselbloem called "extremely surprising, unpleasantly surprising."

The EU executive Commission said the demand stemmed from the fact that the economies of some countries, like Britain, have grown more than expected at the start of the year. Contributions are made according to economic size. Dijsselbloem, however, stressed a revision of source material and ways of computing.

Whatever the cause, Cameron and his Dutch counterpart Mark Rutte already discussed a common protest at the EU summit, which ends Friday. The Netherlands too is facing an increasingly vocal anti-EU camp.

"We are not going to take this lying down," Dijsselbloem said.

The EU's executive Commission said the calculations were an exercise, "a method approved by the member states," said spokesman Patrizio Fiorilli.

He said the gross domestic product of Britain and the Netherlands were "a lot higher than they thought themselves at the beginning of the year, so their contributions were revised upward."

A longtime reluctant member of the EU, Britain has seen a surge in the popularity of the UKIP party, which wants to get Britain out of the EU, claiming its bureaucracy is profligate.

"The EU is like a thirsty vampire feasting on U.K. taxpayers' blood. We need to protect the innocent victims, who are us," said UKIP leader Nigel Farage.

The request for the budget top up comes at a time when Cameron has been telling his EU counterparts how well the British economy is doing in the face of the flagging fortunes on the continent, where even Germany is facing sagging growth.

Official figures on Friday showed Britain's economic recovery is continuing despite a gloomy world environment. Gross domestic product grew 0.7 percent in the three months through September compared with the previous three months, remaining among the strongest growth rates among developed economies.

Treasury Chief George Osborne said the figures show Britain "continues to lead the pack in an increasingly uncertain global economy."

Danica Kirka contributed from London. Raf Casert can be followed on Twitter at http://www.twitter.com/rcasert