WASHINGTON - The Obama administration said on Tuesday that it would request Congress to raise the federal government's borrowing limit by $1.2 trillion this week, fresh evidence of the mounting budgetary pressure facing the world's largest economy.

If approved by Congress, the increase would boost the federal government's borrowing capacity to 16.4 trillion dollars, said a senior Treasury Department official.

Treasury figures revealed that the federal government was expected to come within 100 billion dollars of the current 15.2- trillion-dollar debt ceiling by the end of this year.

After months of contentious partisan wrangling, Republicans and Democrats this summer agreed to increase the federal government's borrowing limit by 2.1 trillion dollars from about 14.3 trillion dollars in three steps.