WASHINGTON, Jan 20 (Reuters) - The world's most powerful government shut down on Saturday after President Donald Trump and the U.S. Congress failed to reach a deal on funding for federal agencies, highlighting the country's deep political divisions.

For the first time since October 2013 - when a similar standoff that lasted 16 days kept only essential agency operations intact - federal workers were being told to stay at home or in some cases to work without pay until new funding is approved.

The shutdown began a year to the day after Trump was sworn in as president. 

His inability to cut a deal despite having a Republican majority in both houses of Congress marks arguably the most debilitating setback for his crisis-plagued administration.

Democrats had insisted that any bill to renew government funding also contain permanent protections for approximately 700,000 young, undocumented immigrants who were brought illegally into the United States as children.

Last week, Trump rejected a bipartisan Senate deal that would have accomplished that as well as hand the White House $2.7 billion in new money for immigration enforcement at America's borders.

Minutes before Friday's midnight deadline for a funding deal, Trump's White House issued a statement blaming Democrats for the shutdown. "We will not negotiate the status of unlawful immigrants while Democrats hold our lawful citizens hostage over their reckless demands," it said.

The shutdown was cemented when the Senate, meeting late into Friday night, blocked a bill to maintain the federal government's funding through Feb. 16.

The vote was 50-49, well short of the 60 needed in the 100-member chamber to vault the bill over a procedural hurdle.

Four Republicans joined most Democrats in killing the measure. A fifth Republican, Senate Majority Leader Mitch McConnell, voted "no" too, but only as part of a parliamentary maneuver to make it easier to bring another bill to the floor.

The breakdown ended a long day of closed-door meetings in Congress and at the White House.

Even as they promised to work on getting the government back up again as soon as possible, Republicans and Democrats blamed each other for the predicament.

BLAME GAME

Senate Majority Leader Mitch McConnell joined Trump in attacking Democrats.

"What we've just witnessed on the floor was a cynical decision by Senate Democrats to shove aside millions of Americans for the sake of irresponsible political games," McConnell said.

Senate Democratic Leader Chuck Schumer said his party took significant steps to reach a deal, including raising the possibility of funding for Trump's proposed wall along the U.S. border with Mexico, which they have ardently opposed.

"It's almost as if you were rooting for a shutdown," Schumer said in comments on the Senate floor aimed directly at Trump.