President Donald Trump signed a new travel ban into law on Monday that bans people from six Muslim-majority countries from entering the United States for 90 days.

The ban will also apply to all citizens of the six countries, including refugees, who are not nationals of those countries.

The new restrictions will also bar people from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.

They were initially signed by Trump, a Republican, but have been challenged by a coalition of Democratic lawmakers and civil rights groups.

Democrats and civil society groups have said the ban is unconstitutional.

Trump tweeted that the new restrictions are being challenged in the courts and that “our courts will ultimately decide.”

“The courts will have to decide, and they will have a very hard time, in this case, to overturn the decision that President Trump has made.

We will fight to make sure that this law is upheld,” he tweeted.

Democratic Sen. Chris Coons of Delaware said the new travel restrictions “may be the most extreme and dangerous order we have ever seen.”

“As a nation, we are deeply saddened by the executive order that President Donald J. Trump signed today,” Coons said in a statement.

“The president’s decision to place a travel ban on citizens of Iran, Libya and Somalia, and a ban on Syrian refugees, is un-American, unconstitutional and dangerously misguided.

I urge the President to immediately withdraw this dangerous order and allow the courts to resolve this issue in a fair and lawful manner.””

There is no justification for a travel restriction in the United State of America.

This executive order is unlawful and the courts must act swiftly to ensure that Americans are not subjected to unnecessary and unfair restrictions on their travel, work, and other freedoms,” he said.

In addition to the new ban, Trump signed an order Tuesday that bans travelers from seven Muslim-dominated countries from returning to the United Kingdom.

The order, signed by Attorney General Jeff Sessions, also bans refugees from Syria indefinitely.

Sessions said Tuesday that the travel ban would not apply to people from Syria, Iraq and Yemen, but the Trump administration later revised that statement to say the ban would apply to refugees from those countries as well.

In an interview on CNN, Coons and Sen. Richard Blumenthal, D-Conn., said the president was trying to make the case to the American people that this was a temporary ban and that people who want to come to the U.S. should not be prevented from doing so.

“We have seen people with family members, spouses, friends, and coworkers who were able to come here, and those people who were denied entry are now being denied entry to the country, so I think it’s a very serious concern,” Blumenthal said.