U.S. Treasury Department officials say the White House plans to ask Congress for a $1.2-trillion increase in the government's debt limit to allow the United States to pay its bills on time.

Treasury officials said Tuesday that the White House will make the request by the end of the week and that the increase is necessary because the government will be within $100 billion of its current limit by then.

The debt limit currently stands at $15.2 trillion and would increase to $16.4 trillion with the request. The limit is what the government can borrow to finance its operations. 

As part of an agreement that ended a huge political wrangle over the debt limit earlier this year, the limit will be increased unless both houses of Congress pass a bill blocking the action.

Also this year, credit rating agency Standard and Poor's downgraded the U.S. credit rating for the first time ever, from the top rank of AAA to AA+. The downgrade was accompanied by an S&P report criticizing the U.S. debt levels, political infighting and the raising of the debt ceiling.