At the end of this year or early next year

U.S. Congress would never give up its control over raising the federal government's debt limit to enhance U.S. fiscal sustainability, John Boehner, speaker of the U. S. House of Representatives, said here on Thursday.

"Congress is never going to give up our ability to control the purse," Boehner said at a press conference on Capitol Hill, adding that the debt limit ought to be used to bring "fiscal sanity" to Washington.

The top GOP lawmaker of the lower chamber refuted U.S. President Barack Obama's request for permanent authority to increase federal government borrowing, a proposal made during the ongoing fiscal negotiation between Democrats and Republicans.

Boehner criticized Obama was "not serious" about the negotiation and has not specified enough spending reductions to strike a deal to avert the "fiscal cliff."

Unless the Congress acts by the end of this year, a combination of tax hikes and sweeping spending cuts dubbed the "fiscal cliff", with a combined amount of about 600 billion U.S. dollars, is set to kick in. Democrats and Republicans have so far locked horns over how to reduce the nation's public debt hovering at 16.2 trillion dollars and tide over the "fiscal cliff." 

At the end of this year or early next year, the United States will be confronted with another fiscal challenge of raising its public debt limit again. It is currently about 200 billion U.S. dollars below the 16.4 trillion dollars legal amount the federal government is allowed to borrow.

In Democrats' proposal made last month to avoid the "fiscal cliff", the Obama administration has asked for the power to raise U.S. debt limit without congressional approval.