By Jeff Mason

WASHINGTON (Reuters) - President Barack Obama met with Republican Speaker of the House of Representatives John Boehner on Sunday at the White House to negotiate ways to avoid the "fiscal cliff," according to White House officials and a congressional aide.

The two sides declined to provide further details about the unannounced meeting. Obama and Boehner aides used the same language to describe it.

"This afternoon, the president and Speaker Boehner met at the White House to discuss efforts to resolve the fiscal cliff," White House spokesman Josh Earnest said.

"We're not reading out details of the conversation, but the lines of communication remain open," he said.

An aide to Boehner emailed an identical quote.

The two sides are trying to reach an agreement that would stop automatic spending cuts and tax increases from going into effect at the beginning of the year. Analysts say if that so-called "fiscal cliff" occurs, the U.S. economy could swing back into a recession.

Obama has made clear he will not accept a deal unless tax rates for the wealthiest Americans rise. Boehner and many of his fellow Republicans say any tax increases would hurt a still fragile economy.

Last week Boehner and Obama spoke by phone, a conversation that the Republican leader described as pleasant but unproductive.

The common language used by both men's aides suggests an agreement to keep details about their discussions private, which could help both of them sell less politically palatable aspects of an eventual deal to lawmakers in their respective parties.

(additional reporting by Rachelle Younglai; editing by Stacey Joyce)