(Adds Schumer quote, deal)
WASHINGTON, Jan 22 (Reuters) - U.S. lawmakers struck a deal to reopen the federal government three days into a shutdown prompted by an impasse over immigration and border security, the Senate Democratic leader said on Monday.
"We will vote today to reopen the government," Minority Leader Chuck Schumer told the Senate.
Democrats had insisted that any short-term spending legislation to keep the government running include protections for young undocumented immigrants known as "Dreamers."
Republicans in turn said they would not negotiate on immigration until Democrats gave them the votes needed to reopen the government.
Funding for government operations expired at midnight on Friday and lawmakers worked through the weekend in vain. The outlines of a deal began emerging as a bipartisan group of senators held talks on Sunday and Monday morning.
Tens of thousands of federal workers had begun closing down operations on Monday, the first weekday since the shutdown, but essential services such as security and defense operations continued.
Schumer said he had come to an arrangement with Senate Republican Leader Mitch McConnell on the funding bill to keep the government open until Feb. 8 and a plan to address the issue of the Dreamers.
(Additional reporting David Morgan, Ginger Gibson, Susan Heavey, Diane Bartz, Megan Davies, Lucia Mutikani, Yasmeen Abdutaleb; Writing by Doina Chiacu; Editing by Alistair Bell)