The entrance to the Smithsonian's Enid A. Haupt Garden is padlocked as a partial government shutdown continues, in Washington, U.S., January 7, 2019.

Federal employee Ashaki Robinson addresses the partial U.S. federal government shutdown during a roundtable with U.S. Senator Chris Van Hollen (D-MD) (not pictured) at his suburban Washington office in Largo, Maryland, U.S. January 7, 2019.

The figure of a panda is seen behind a sign telling the public that the National Zoo is closed due to the partial government shutdown in Washington, U.S., January 2, 2019.

U.S. President Donald Trump looks out at reporters in the Rose Garden as he speaks after a meeting with U.S. Congressional leaders about the government shutdown at the White House in Washington, U.S., January 4, 2019.

A woman passes a sculpture as she walks away from the doors of the National Gallery of Art which remains closed due to the partial government shutdown in Washington, U.S., January 8, 2019.

A father and child stand outside the National Air and Space Museum, closed, due to the partial U.S. government shutdown fight between Congress and President Trump, over his demand of funding for a border wall, in Washington, U.S. January 2, 2019.

Tourist Gregg Van Ler of New Jersey works out on the steps of the National Gallery of Art which is closed due to the partial government shutdown in Washington, U.S., January 4, 2019.

Federal employee Tyra McClelland addresses the partial U.S. federal government shutdown during a roundtable with U.S. Senator Chris Van Hollen (D-MD) (not pictured) at his suburban Washington office in Largo, Maryland, U.S. January 7, 2019.

A sign declares the National Archive is closed due to a partial federal government shutdown in Washington, U.S., December 22, 2018.

A worker picks up trash on the National Mall near the U.S. Capitol building as the partial government shutdown continues in Washington, U.S., January 6, 2019.

The U.S. flag flies over Federal Hall National Memorial, as the partial U.S. government shutdown continues in New York, U.S., January 7, 2019. REUTERS/Brendan McDermid

A sign is seen on a fence at the General Grant National Memorial, for former U.S. President Ulysses S. Grant, as the partial U.S. government shutdown continues, in Manhattan, New York City, New York, U.S., January 7, 2019.

U.S. President Donald Trump confers with Vice President Mike Pence and House Minority Whip Steve Scalise (R-LA) as they faced to reporters in the Rose Garden after the president met with U.S. Congressional leaders about the government shutdown and border security at the White House in Washington, U.S., January 4, 2019. Reuters/Carlos Barria

People look inside as a closed sign is seen on a door at Federal Hall National Memorial, as the partial U.S. government shutdown continues in New York, U.S., January 7, 2019.

Tourists view the sculpture Hahn/Cock by Katharina Fritsch at the National Gallery of Art, scheduled to close the next day, due to the partial U.S. government shutdown fight between Congress and President Trump, over his demand of funding for a border wall, in Washington, U.S. January 2, 2019.