WASHINGTON -  The Department of Justice is deploying 50 judges to immigration detention facilities across the United States, according to two sources and a letter seen by Reuters and sent to judges.

The department is also considering asking judges to sit from 6am to 10pm, split between two rotating shifts, to adjudicate more cases, the sources said. A notice about shift times was not included in the letter.

The Justice Department did not respond to a request for comment.

On Jan. 25 President Donald Trump issued an executive order aimed at speeding up deportations and holding migrants in detention until their cases can be heard. Trump campaigned on a pledge to get tougher on the estimated 11 million illegal immigrants, playing on fears of violent crime while promising to build a wall on the border with Mexico and to stop potential terrorists from entering the country.

The order called for the end of a policy known as “catch and release,” by which immigrants were released from detention and given a date to appear in court. Immigration courts have a backlog of over 550,000 cases, according to the Justice Department’s data, so many court dates are set years into the future.

Judges are employed by the Justice Department to oversee cases that determine if immigrants are given protections, such as asylum, or ordered deported. A handful of judges work from detention centres but most work from courts around the country.

Two sources familiar with the Justice Department’s plan said the department would ask more judges to volunteer for one or two month deployments at detention centres. If the department cannot find enough volunteers, the department would assign judges to detention centres, the sources said.

Judges who volunteer for the first 50 deployments would be sent to detention centres in Adelanto, California; San Diego, Chicago and elsewhere, according to the letter.

Republican Trump’s policy on immigrants has been criticized by Democratic lawmakers and advocates for immigrants, who said he was jeopardizing the rights and freedoms of millions while treating Mexico as an enemy, not an ally, and damaging the country’s reputation as a welcoming place for immigrants.

Meanwhile, several states have said they would move forward with legal challenges to a revised executive order signed by President Donald Trump this week that temporarily bars the admission of refugees and some travelers from a group of Muslim-majority countries.

The new travel order, which is set to take effect on March 16, replaced a more sweeping ban issued on Jan. 27 that caused chaos and protests at airports.

The first order was hit by more than two dozen lawsuits, including a challenge brought by Washington state and joined by Minnesota. In response to Washington’s lawsuit, US District Judge James Robart in Seattle ordered an emergency halt to the policy last month. That ruling was upheld by an appeals court in San Francisco. Washington state Attorney General Robert Ferguson said on Thursday he planned to ask Robart to confirm that his ruling would also apply to Trump’s revised order, which would halt it from being implemented.

Ferguson told a news conference the new order harmed a “smaller group” of individuals but that would not affect the state’s ability to challenge it in court. He said the burden was on the Trump administration to show that the court ruling from last month did not apply to its new policy. A US Department of Justice spokeswoman declined to comment on pending litigation. The government has said the president has wide authority to implement immigration policy and that the travel rules are necessary to protect against terrorist attacks. The states and immigration advocates argue the new ban, like the original one, discriminates against Muslims. New York’s attorney general, Eric Schneiderman, said on Thursday he would be joining Washington’s lawsuit against the new ban and the state of Oregon said it would join too.

The attorney general for Massachusetts, Maura Healey, said on Twitter she would be joining Washington’s challenge to “Trump’s unlawful #MuslimBan2.”

Minnesota is also continuing to pursue the Seattle case alongside Washington.

During his presidential campaign, Trump called for “a total and complete shutdown of Muslims entering the United States.” He later toned down that language and said he would implement a policy of “extreme vetting” of foreigners coming to the country.

The opposition from the states comes on top of a separate legal challenge to the new ban brought by Hawaii on Wednesday. Hawaii had also sued over the previous order and is seeking to amend its complaint to include the new ban.

A hearing in that case is set for next Wednesday, a day before the clock starts on the new order.

Trump’s new executive order was designed with the intention of avoiding the legal hurdles.

While the new order keeps a 90-day ban on travel to the United States by citizens of Iran, Libya, Syria, Somalia, Sudan and Yemen, it excludes Iraq.

Refugees are still halted from entering the country for 120 days, but the new order removed an indefinite ban on all refugees from Syria.

The revisions include explicit exemptions for legal permanent residents or existing visa holders. Waivers are allowed on a case-by-case basis for some business, diplomatic and other travelers.

The first hurdle for the lawsuits will be proving “standing,” which means finding someone who has been harmed by the policy. With so many exemptions, legal experts have said it might be hard to find individuals who would have a right to sue, in the eyes of a court.