U.S. President Barack Obama has formally notified Congress that he plans a $1.2-trillion increase in the nation’s debt limit.

The debt ceiling is the legal amount of money the U.S. government can borrow.

President Obama said in a letter to congressional leaders Thursday that further borrowing is required to meet existing commitments. The United States came within $100 billion of its current ceiling of $15.2 trillion at the end of last year.

Mr. Obama originally planned to make the request last month, but granted top lawmakers from both parties more time to allow both houses to vote on a largely symbolic bill allowing some legislators to express their opposition to increasing the limit.

Congress has 15 days to reject the president’s request.

The proposed $1.2-trillion increase in the borrowing authority is likely to pass despite the objections. The debt limit would rise to $16.4 trillion with the request.