A panel of United Nations human rights experts said Wednesday that President Trump’s sweeping order restricting some travelers and refugees from entering the United States violates the country’s international human rights obligations.

The blunt assessment from the U.N. is the latest criticism it has volleyed at Trump’s ban, which temporarily closes America’s borders to people from seven Muslim-majority nations and suspends admission for almost all refugees for a 120-day period.

“Such an order is clearly discriminatory based on one’s nationality and leads to increased stigmatization of Muslim communities,” a group of U.N. Special Rapporteurs — experts appointed to study human rights issues — said in a statement. The group includes rapporteurs on migrants, human rights and counterterrorism, racism, torture and freedom of religion.

Trump and officials in his administration have argued since he signed the order last Friday that the measure is not a “Muslim ban.” During the presidential campaign, Trump called for a Muslim ban, a statement that remains on his campaign website, and he said the day he signed the order that he would prioritize Christians seeking admission as refugees.

In its statement, the group of U.N. experts alluded to people who have been detained at airports across the country, saying they were worried people flying to the United States “will be subject to detention for an undefined period of time and then ultimately deported.”

A spokesman for the United States mission to the U.N. did not respond to a request for comment Wednesday.

U.N. officials have spoken out against the ban in very sharp terms this week, worrying about its impact on refugees and expressing concerns it could help terrorist groups. Zeid Ra’ad Al Hussein, the U.N. high commissioner for human rights, called the travel ban “mean-spirited” on Monday, while U.N. Secretary-General António Guterres released a statement a day later saying he was worried about decisions “undermining the integrity of the international refugee protection regime.”

Trump’s order included a temporary entry ban on people from seven countries: Iraq, Iran, Syria, Yemen, Sudan, Libya and Somalia. It also significantly cut back the number of refugees the United States will take in and, in addition to a 120-day freeze on most refugee admissions, indefinitely suspended the arrival of any Syrian refugees.

The U.N. has called the situation in Syria “the worst war, the worst humanitarian crisis, the worst displacement crisis, the worst refugee crisis in a generation,” and the experts Wednesday called Trump’s order “a significant setback for those who are obviously in need of international protection.”

They also expressed their concerns about what would happen to refugees left in limbo, referring to “non-refoulement,” a principle the U.N. has long held stating that nations cannot expel or return a refugee to an area where their life or freedom are threatened.

The experts wrote that the immigration policy “risks people being returned, without proper individual assessments and asylum procedures, to places in which they risk being subjected to torture and other cruel, inhuman or degrading treatment, in direct contravention of international humanitarian and human rights laws which uphold the principle of non-refoulement.”

The Trump administration said Tuesday that 872 refugees considered in transit and who would face “undue hardship” if turned back would be allowed into the United States by week’s end. The U.N. refugee agency, in a statement this week, said that Trump’s order could impact a far larger number of people, estimating that some 20,000 refugees might have been resettled in the United States during the 120-day window when most won’t be allowed to enter the country.

Further reading:

Trump’s refugee ban is a matter of life and death for some, including a 1-year-old with cancer

Officials worry that U.S. counterterrorism defenses will be weakened by Trump actions

Trump has fired the acting attorney general who ordered Justice Dept. not to defend president’s travel ban

Hundreds of lawyers descend on airports to offer free help after Trump’s executive order

Trump and his aides keep justifying the entry ban by citing attacks it couldn’t have prevented