World  - The American Civil Liberties Union and other advocacy groups have sued the administration of President Donald Trump in an attempt to block a new rule that would prevent almost all migrants from seeking asylum inside the United States.

The US Department of Homeland Security, in a statement issued on Monday, said the new rule requires asylum-seekers to have first applied for asylum and been rejected in one of the countries they traveled through before becoming eligible to apply in the United States

The lawsuit, filed on Tuesday in US District Court for the Northern District of California, said the sweeping new rule violates US and international law on several fronts.

The lawsuit names US Attorney General William Barr and a number of US immigration officials as defendants.

"This is the Trump administration's most extreme run at an asylum ban yet. It clearly violates domestic and international law, and cannot stand," ACLU attorney Lee Gelernt said in a statement.

The ACLU, the Southern Poverty Law Center and the Center for Constitutional Rights filed the lawsuit on behalf of immigrant support groups East Bay Sanctuary Covenant, Al Otro Lado, Innovation Law Lab and Central American Resource Center.

The suit argues that US law establishes that an asylum-seeker can only be required to seek protection in another country under two conditions: when the United States has a "safe third country" agreement in place with that state, or when the asylum-seeker has firmly resettled in another country.

The suit also says that merely traveling through a country is insufficient to establish someone has firmly resettled there. As a result, the new rule would force people to return to countries "that are rife with danger and violence," the suit says.

The United States is seeking "safe third country" agreements with Mexico and Guatemala, but they have resisted.

Other attempts by Trump to curb legal and illegal immigration have received mixed results in federal courts. The Republican president lost a court battle to deny asylum to anyone who crossed the US-Mexico border illegally, but he was able to eventually bar most immigrants from several Muslim-majority countries after the US Supreme Court allowed his travel ban to take effect.

Trump has made his hard-line stance on immigration an integral part of his presidency and has promised to build a wall along the US-Mexican border to curb the flow of migrants from Mexico and Central America.