First day of U.S. government shutdown ends in standoff

* Schumer on Trump: "like negotiating with Jell-O"

* Trump: "Democrats wanted to give me a nice present"

* McConnell: "We'll be right back at this tomorrow" (Adds McConnell on Monday vote, Connelly, Trump campaign ad)

By Richard Cowan and Ginger Gibson

WASHINGTON, Jan 20 (Reuters) - President Donald Trump and Republican lawmakers were locked in a standoff with Democrats on Saturday over the U.S. government shutdown, with Republicans saying they would not negotiate on immigration until the government is reopened.

Funding for federal agencies ran out at midnight with no agreement in Congress, meaning the second year of Trump's presidency began without a fully functioning government.

Democrats stuck to demands that any short-term spending legislation must 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.

U.S. government workers were told to stay home or, in some cases, work without pay until new funding is approved in the first federal government shutdown since a 16-day funding lapse in October 2013.

The Republican-controlled Senate and House of Representatives held rare weekend sessions on Saturday, facing a political crisis that could affect November congressional elections. By about 7 p.m. both chambers resigned themselves to failure and agreed to resume work on Sunday.

Both Republicans and Democrats had dug in during the day, each side blaming the other.

Senate Majority Leader Mitch McConnell said the Senate would vote at 0100 EST (0600 GMT) Monday on a bill to fund the government through Feb. 8, unless Democrats agree to hold it sooner.

"We'll be right back at this tomorrow and for as long as it takes" for Democrats to vote for legislation that would reopen the government, McConnell said.

Outside the U.S. Capitol, parks, open-air monuments and Smithsonian museums were open as a second annual women's rights march took place on the National Mall. But visitors were turned away from the Liberty Bell in Philadelphia and the Statue of Liberty and Ellis Island in New York Harbor.

A scheduled trip by Trump and some Cabinet members to the World Economic Forum in Davos, Switzerland, was being assessed on a day-to-day basis, White House budget director Mick Mulvaney said.

Republicans said they would refuse to negotiate on immigration until Democrats provide the votes to re-open the government. Democrats insisted they have been willing to compromise but Republicans backed out of deals.