(Recasts with budget deal reached)
WASHINGTON, Feb 7 (Reuters) - The U.S. Senate on Wednesday reached a two-year bipartisan budget deal worth around $300 billion that would lift caps on defense and domestic government spending in an attempt to end the kind of squabbling over fiscal issues that has plagued Washington for years.
"This bill is the product of extensive negotiations among congressional leaders and the White House," Senate Majority Leader Mitch McConnell, a Republican, said on the Senate floor. "We worked hard to find common ground and remained focused on serving the American people."
Chuck Schumer, the leader of the Senate Democrats, said the deal should break the cycle of partisan fights over spending. But Democrats in the House of Representatives have warned that they will not back it unless Republican Speaker Paul Ryan promises to advance separate legislation on immigration policy.
The higher defense spending should allow President Donald Trump to make good on a campaign promise for a U.S. military build-up. His fellow Republicans control both chambers of Congress.
The agreement also provides funds for disaster relief, infrastructure and programs addressing opioid abuse, the Senate leaders said.
A congressional source familiar with the agreement said it would increase non-defense spending by $131 billion and include $20 billion for infrastructure spending. It also would extend funding for the Children's Health Insurance Program (CHIP) for 10 years instead of the current six, the source added.
Passage of the plan would ease the brinkmanship over spending that roils Washington so regularly that financial markets barely flinch anymore at the threat of a government shutdown.
Aside from the two-year deal that would have to be approved by the full Senate and House, lawmakers were also trying to reach agreement by Thursday to avoid a shutdown and fund the government until March 23.
(Additional reporting by David Morgan, Susan Heavey and Doina Chiacu; Writing by Alistair Bell; Editing by Will Dunham)