President Barack Obama and Speaker John A. Boehner, R-Ohio, met for almost an hour Thursday evening at the White House in what aides called a “frank” discussion on the ongoing fiscal cliff negotiations.

The two sides released no information after the 50-minute session, the second face-to-face meeting they have held in the past week on a deal to extend expiring tax cuts and replace scheduled across-the-board spending cuts triggered by the last major congressional budget negotiations.

Treasury Secretary Timothy F. Geithner and Rob Nabors, the White House liaison to Congress, also attended the meeting, which came near the end of the week in which talks were reported at times to be at an impasse even as both sides traded offers and counteroffers.

“The president and speaker had a frank meeting in the Oval Office tonight,” a spokesman for Boehner said. “It lasted approximately 50 minutes. There will be no further readout of the meeting, but lines of communication remain open.”

Obama and Boehner also met Sunday evening at the White House and spoke by phone on Monday. as they reportedly traded offers and counteroffers.

Earlier Thursday, National Economic Council Director Gene Sperling spoke to Senate Democrats in one of their weekly caucus lunches, according to two sources.

Members have been especially tight-lipped — and have been kept mostly out of the loop — about the ongoing talks. When asked whether there was any news, one Democratic senator exiting the lunch said, “none.”

Most sources, regardless of party, believe it is unlikely a deal will be struck before Christmas. That Boehner and Obama met for the second time in five days, however, appears promising, given that they have each accused the other not being “serious” about talks to avert the fiscal cliff.

Daniel Newhauser and Alan K. Ota contributed to this report.