The Trump government issued an order on Friday to limit asylum at the US border with Mexico by requiring that anyone illegally entering the US should not be eligible for asylum.
The American Civil Liberties Union and other legal groups filed a lawsuit on Friday afternoon against the federal court administration in Northern California to block the rules because the measures were clearly illegal.
"We need people in our country, but they must come in legally and have merit," Trump said Friday as he prepared to leave for Paris.
Administrative officers say that the measures have been in force for at least three months, but can be extended. They go into effect on Saturday and do not affect people who are already in the country.
The Ministries of Homeland Security (DHS) and Justice (DOJ) said that the president has the authority to limit the suitability for asylum and can do so through proclamation.
The administration uses part of the Immigration Act to justify its action.
Section 212 (f) says that when the president considers the entry of immigrants "harmful to the interests of the United States", he will, in the proclamation, and for the period he deems necessary, the entry of all foreigners or a class of foreigners as immigrants or non-immigrants, or upon entry of foreign nationals, to impose restrictions that it deems appropriate. "
Section 212 (f) is the same law used by the Trump administration to justify its ban on travel to mainly Muslim countries.
"If they actually change that rule, we at ACLU, along with other organizations, are ready to be part of the federal court to challenge that immediately," American Civil Liberties Union of Texas Policy Counsel Shaw Drake told VOA.
Drake sees the move as an attempt to stop a caravan of migrants going through Mexico to the border with the United States.
The caravan has been a focus of Trump, who called it an "invasion" and an "emergency". Trump often quoted the caravan and the alleged threat during the run-up to the Tuesday election.
"Everyone traveling in the caravan should not be treated differently from all other asylum seekers seeking protection in the United States," Drake said. "Again, there is a legal process for people to continue and the Customs and Border Patrol and all government agencies must follow the law, regardless of whether the person is supposed to travel as part of the caravan or not."
If we call the situation at the border "with every definition, a full-blown and very large crisis", officials said that it would be easier for asylum seekers to access treatment via access ports, because more resources are available.