WASHINGTON (Reuters) -Top U.S. Senate Democrat Chuck Schumer on Thursday said he would vote to advance a Republican stopgap funding bill, signaling that his party would provide the votes to avert a government shutdown.

"I will vote to keep the government open and not shut it down," he said in a speech to the Senate.

Schumer acknowledged the difficulty of his decision, which will put him on record as supporting a bill that was written only by Republicans and has drawn fierce attacks from Democrats. The bill passed the Republican-controlled House of Representatives earlier this week.

At a press conference later on Thursday, Schumer did not provide details on how other Senate Democrats would vote on Friday before a midnight deadline when current funding expires for programs other than Social Security retirement benefits and Medicare and Medicaid health insurance for the elderly, poor and disabled.

"As members study it (the bill) and look at it, each is making his own decision," the New York Democrat said.

Schumer said he was still discussing with Republican Senate Majority Leader John Thune the possibility of senators being allowed to present amendments to the bill.

On Wednesday, Schumer floated the idea of Democrats offering an amendment for a one-month extension of current funding, instead of Republicans' approach of a 6-1/2-month extension, through the fiscal year that ends on September 30. The aim would be to give senators more time to write detailed bills tailored for this fiscal year instead of relying mainly on last year's approach to spending.

But Democrats are unlikely to have the votes to pass such an amendment even if it is allowed to be voted upon.

Blocking the Republican bill that was passed by the House on Tuesday would have required the support of at least 41 of Schumer's Democrats and would have triggered a partial government shutdown, which Democrats have long opposed as needless chaos. 

Democrats' wariness of a shutdown was heightened by Republican President Donald Trump's rapid-fire campaign to unilaterally shutter many federal operations, which Democrats note is already causing disruption.

In laying out his rationale for voting for a spending bill that Democrats say short-changes social safety net programs, Schumer told reporters: "In effect, a shutdown gives Trump and his minions the keys to the city and the country and I thought that had to be avoided."

Schumer said it would have allowed the White House and billionaire Elon Musk, whom Trump has charged with sweeping powers to cut government staffing levels and costs, to decide which federal agencies to reopen and when.

The White House did not immediately comment on Schumer's announcement.