UK challenges new EU demand for 2013 budget cash
The UK government says it will fight an EU demand for an extra 11.2bn euros (£9.5bn; $14.4bn) from member states to settle unpaid EU bills this year.
The UK contribution to that would be about 1.2bn euros.
"You can be very clear we will fight it," a Downing Street spokeswoman said, reacting to the proposal from EU Budget Commissioner Janusz Lewandowski.
MEPs back the Commission in saying the extra - called an amending budget - must be paid to cover the 2012 bills.
The MEPs have not yet approved the EU's multi-year budget for 2014-2020. The 3.3% cut in the multi-year budget, agreed by EU governments last month, will not get through the European Parliament unless the amending budget is agreed first, MEPs say.
UK Prime Minister David Cameron played a key role in pushing for the budget cut, arguing that the increase proposed by the Commission was unacceptable while national budgets were being trimmed to reduce Europe's debt mountain.
The EU's 2013 budget - separate from the multi-year budget - was agreed last December. It was set at 132.8bn euros - a 2.4% increase on the 2012 budget.
The draft amending budget can be adopted if a qualified majority of member states support it - meaning that the UK can be outvoted.
The Commission says an extra 9bn euros is needed for cohesion - that is, development projects in the EU's poorer regions - and an extra 2.2bn "to cover needs in practically all other areas of the budget, with the exception of administration, where no additional requests have been made".
Mr Lewandowski said that in recent years EU budgets had been "increasingly below the real needs based on estimates from member states; this is creating a snowballing effect of unpaid claims transferred onto the following year".
"The ostrich policy can only work for so long: postponing payment of a bill will not make it go away," he argued.