One of the many executive orders President Donald Trump signed on Monday included one to end birthright citizenship. Here's what to know about it and why lawsuits have already been filed.

The president issued several actions related to the border or immigration, including ramping up deportations and suspending refugee resettlement.

Residents in Hackensack, New Jersey gathered Tuesday to protest President Donald Trump's executive order ending birthright citizenship.

Immigration rights groups, including the American Civil Liberties Union, sued the Trump administration soon after the president signed an executive order on immigration that would end birthright citizenship for children born in the U.

Attorneys general in 18 states sued Tuesday to block the order, saying birthright citizenship cannot be undone with the stroke of the president’s pen.

California Attorney General Rob Bonta announced the state would join a lawsuit in the wake of an executive order by President Trump seeking to end birthright citizenship.

Maryland joined 17 states, Washington, D.C., and San Francisco to sue President Trump on Tuesday over what they called his “flagrantly unlawful attempt” to end birthright citizenship through one of the flurry of executive orders he signed after taking office.

"Birthright citizenship in our country is a guarantee of equality, born out of a collective fight against oppression," Attorney General Andrea J. Campbell said in a statement.

President Donald Trump's executive order seeks to end birthright citizenship for some children born to immigrants.

President Trump promised Monday to take aggressive action to curb the number of undocumented migrants in the US, and one of the bigger initiatives revolves around what's known as birthright citizenship.