U.S. President Barack Obama says the top Republican in the House of Representatives has broken off negotiations to raise the U.S. borrowing limit despite the president offering what he called “an extraordinarily fair deal.”

Mr. Obama said Friday it is “hard to understand” why House Speaker John Boehner would “walk away from this kind of deal.” The president said they are now out of time. He said he has called the top congressional leadership from both parties to a meeting Saturday at the White House . The president says he wants the lawmakers to explain to him how the country will avoid defaulting on its payments after the government runs out of money on August 2.

Mr. Obama says he had proposed significant cuts in discretionary spending and from social welfare programs. He said he also had proposed increasing tax revenue by a lower amount than had been agreed to by a bipartisan group of senators.

He said top Democrats in Congress had not agreed to the deal but were willing to negotiate. He said if Republicans refuse to help find a compromise, they will be to blame for any negative consequences if the government cannot send out the 70 million checks it writes each month.

Shortly after, Speaker Boehner responded, saying President Obama's proposal had demanded an unacceptable increase in tax revenue that would require raising taxes on the people needed to invest in the economy and create jobs. Boehner said he would work with members of both parties this week to chart a “path forward,” saying he is “confident” the U.S. can avoid defaulting on its payments.

Mr. Obama reiterated that he will not accept a short-term increase to the debt ceiling, saying at minimum the government needs to allow enough borrowing to get the U.S. into the next presidential term in 2013.

He said he is willing to go along with a back-up plan proposed by the top Republican in the Senate, Mitch McConnell, that would give Mr. Obama the power to raise the debt limit while allowing Republicans to vote against the increase. He said this would accomplish the minimum necessary of allowing the U.S. to keep paying its bills. But he said he preferred to also work on solving the problem of the enormous U.S. debt and deficit.

Earlier Friday, Speaker Boehner blamed Democrats for the impasse, telling reporters Republicans in the House had done their job. Talks have stalled this week over stark disagreements on the need for tax hikes and severe funding cuts to social safety net programs.

Boehner's comment came as Democrats in the Senate blocked a Republican-backed plan from the House of Representatives to raise the debt ceiling in exchange for large cuts in federal spending.

In addition to slashing spending, the bill would have required Congress to approve a constitutional amendment for a balanced federal budget.

The U.S. Treasury Department, the central bank and the White House have all warned a default would have catastrophic consequences for the economy.