Negotiators from the White House and the U.S. Congress continued their efforts Sunday to reach agreement on ways to keep the government from defaulting on its debt.

Five straight days of talks involving U.S. President Barack Obama and Republican leaders in Congress that ended Thursday failed to break the current deadlock.

Experts say Congress must raise the $14.3 trillion debt ceiling by August 2 or the government will run out of money. Economists are warning that default would have serious consequences for both the U.S. economy and for global financial markets.

White House budget director Jack Lew told television interviewers on Sunday that he believes there is still time to, in his words, “get something big done” on a deal.

Both sides are supporting major cuts in government spending. But the president also is seeking increased revenues that would come from raising taxes on wealthy Americans and corporations, something the Republicans steadfastly oppose.

In his weekly address on Saturday, Mr. Obama urged members of Congress to embrace what he called the “shared sacrifice” required to solve the country's debt and deficit problems. He said he is willing to compromise even if it is not politically popular.