House Speaker John A. Boehner (R-Ohio) called on Senate leaders Thursday to bring his so-called "Plan B" up for a vote, if it passes the House Thursday evening.

He said the GOP plan -- which would extend Bush-era tax rates for income above $1 million a year but allow rates to rise for those making more -- would shield more than 99 percent of Americans from a tax hike set to take effect without Congressional action next month.

"When the Senate Democrats and the White House refuse to act, they will be responsible for the largest tax increase in American history," he said.

Competing media events by Boehner and Senate leaders Thursday morning did nothing to resolve the stand-off over the year-end "fiscal cliff."

Democrats said Boehner was forced to move on his GOP-only plan after discovering he did not have Republican support for a broader deficit reduction plan he had proposed to the White House.

Meanwhile, Boehner said Obama had not offered enough in spending and entitlement cuts to match his own concession in allowing some tax rates to rise. Republicans have maintained for years that the Bush era tax rates should be extended at all income levels.

"For weeks, the White House said if I moved on rates, they would make substantial concessions on spending cuts and entitlement reforms," he said. "I did my part. They've done nothing," Boehner said.

In fact, President Obama countered Boehner's offer with a proposal to trim Social Security benefits and also raise the threshold of Americans spared a tax increase from $250,000 to $400,000 a year. But Boehner indicated he sought deeper spending cuts as a trade for his tax concession.