Breaking: Obama, Boehner, Democrats Strike Debt Deal to Head Off Government Default (Video)

Obama announces deal has been reached at 8:40 p.m. at the White House press briefing room. Video:

President Barack Obama announced on Sunday that Democrats and Republicans leaders have reached an agreement to reduce the U.S. deficit and avoid default.

Obama said the agreement will cut about $1 trillion over 10 years.

The bipartisan plan will be presented to Congress on Monday, Senate Majority Leader Harry Reid said.

"Leaders from both parties and in both chambers will present this agreement to our caucuses tomorrow," Reid said on the Senate floor

Other political news of note First Read: 'Very close' to deal that looks a lot like Boehner plan
A GOP source close to the negotiations tells NBC News that both sides are "very close" to agreement on a two-step debt-ceiling deal that's essentially the Boehner plan without the balanced-budget amendment and modified triggers.

"To pass this settlement, we'll need the support of Democrats and Republicans in both the House and Senate. There is no way either party, in either chamber, can do this alone."

Earlier in the day, Reid had warned that "as we know, one problem can stop the whole agreement from going forward.”

And one potential obstacle seemed to be developing: the size of cuts to military spending that might be forced by a "trigger" if Congress couldn’t meet certain deficit reduction targets on its own