WASHINGTON, Feb. 19 (Xinhua) -- Sixteen U.S. states Monday jointly sued U.S. President Donald Trump to challenge his national emergency declaration over funding a wall between the United States and Mexico.

Trump signed a national emergency on Friday to build the U.S.-Mexico border wall and push for his signature campaign promise. The move gave the president power to bypass Congress to get access to money.

The lawsuit, led by California Attorney General Xavier Becerra and filed in the U.S. District Court for the Northern District of California in San Francisco, was joined by attorneys general from Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Michigan, Minnesota, Nevada, New Jersey, New Mexico, New York, Oregon and Virginia.

"Our goal here is simple: we're trying to stop @realdonaldtrump from violating the Constitution, the separation of powers, from stealing money from Americans and states that has been allocated by #Congress, lawfully," Becerra tweeted Monday.

He said the legal action, filed on U.S. Presidents Day, was aimed at preventing Trump from "unilaterally robbing taxpayer funds lawfully set aside by Congress for American people."

Trump announced last week that he will take executive action, including a national emergency, to obtain funds for his long-promised wall on the southern U.S. border.

Democrat-dominated House declined to fulfill Trump's request for 5.7 billion U.S. dollars to help build the wall that the president promised in his 2016 campaign for presidency.

Demonstrations were held Monday in Washington, New York, Chicago and dozens of other U.S. cities against Trump's move.

In New York City, hundreds of people rallied in Union Square to protest against Trump's declaration and decry Trump's proclamation as "undemocratic and anti-immigrant."

Hundreds of protesters chanted outside the White House on Monday, the annual U.S. Presidents Day holiday, as part of the nationwide demonstrations."End the fake emergency now," a banner read. "We stand with immigrants and asylum seekers," another claimed.

Hal Ponder, a Washington, D.C. resident and former Congress employee, told Xinhua that he believes "there is no emergency" at the southern border and that the president is "making this up" to get around Congress to push for his signature campaign promise.

"It's all political. It's not real," said Ponder at Lafayette Square in front of the White House.

White House senior policy adviser Stephen Miller defended Trump in an interview on "Fox News Sunday," insisting the emergency is real.

There have been an "increasing number of people crossing" and "a huge increase in drug deaths" since 2000, he claimed.

Customs and Border Protection officers apprehended close to 400,000 people on the U.S.-Mexico border during the 2018 fiscal year, according to federal data.