WASHINGTON, Jan. 12 (Xinhua) -- U.S. President Barack Obama requested Congress Thursday to raise the federal government's borrowing limit by 1.2 trillion U.S. dollars, as the government is facing mounting budgetary pressure.

It was the third and final such request the president would make under the bipartisan deal inked last August to prevent a government default. If approved by Congress, the increase would boost the federal government's borrowing capacity to 16.4 trillion dollars.

The Obama administration announced late December that it would ask Congress to raise the federal government's borrowing limit within a week, since the debt subject to limit was within 100 billion U.S. dollars. However, in order to allow vacationing lawmakers time to consider the petition, Obama postponed the request.

After months of contentious partisan wrangling, Republicans and Democrats last summer reached agreement to increase the federal government's borrowing limit by 2.1 trillion dollars from about 14. 3 trillion dollars in three steps. The borrowing limit of U.S. federal government was raised in August and September by 400 billion dollars and 500 billion dollars respectively.

The U.S. federal government registered a 1.299 trillion dollars budget deficit for the 2011 fiscal year ending September, with an average of about 108 billion dollars per month.

Treasury figures released Thursday show that the U.S. federal government registered a budget deficit of nearly 86 billion dollars in December, bringing the total budget deficit of the first three months of the 2012 budget year to 321.7 billion dollars.