Sen. Elizabeth Warren this week demanded that U.S. Customs and Border Protection provide details regarding recent reports that Iranians and Iranian Americans have been detained and questioned on religious and political views amid rising tensions between the countries in recent weeks.

In a letter to CBP Acting Commissioner Mark Morgan, the Massachusetts Democrat cited a report from the Council on American-Islamic Relations that on Jan. 4, more than 60 Iranians and Iranian Americans “were detained at length and questioned” while attempting to reenter the United States from Canada.

The alleged hold up occurred just days after a U.S. drone strike ordered by President Donald Trump killed Iranian Gen. Qassem Soleimani, which stoked tensions throughout the Middle East. The situation led the U.S. Department of Homeland Security to issue a National Terrorism Advisory System Bulletin on Jan. 4 stating that “Iran and its partners, such as Hezbollah, have demonstrated the intent and capability to conduct operations in the United States.”

One Iranian-American, Warren wrote, said CBP held and questioned her family at the border crossing for nearly a dozen hours. Advocates said the people held were questioned “about their political views or religious views and practices. There have also been indications of people of Iranian heritage at other ports of entry being held and subjected to enhanced scrutiny since Soleimani’s death," Warren wrote.

CBP issued a statement, posted on Twitter, saying that “social media posts that CBP is detaining Iranian-Americans and refusing their entry into the U.S. because of their country of origin are false. Reports that DHS/CBP has issued a related directive are also false.”

Social media posts that CBP is detaining Iranian-Americans and refusing their entry into the U.S. because of their country of origin are false. Reports that DHS/CBP has issued a related directive are also false. — CBP (@CBP) January 5, 2020

CNN reported that CBP said that the Washington state port of entry experienced increased wait times “to an average of two hours on Saturday evening, although some travelers experienced wait times of up to four hours due to increased volume and reduced staff during the holiday season.”

The agency said that “based on the current threat environment, CBP is operating with an enhanced posture at its ports of entry to safeguard our national security and protect the American people while simultaneously protecting the civil rights and liberties of everyone.”

But Warren argued those statements were not clear enough.

“The new threat warning from DHS is serious, and CBP should be taking lawful and appropriate action to protect national security,” Warren wrote. “But the conflicting information circulating about CBP personnel’s treatment of Iranian Americans and people who are or are perceived to be of Iranian heritage raises questions about what agency policies are in effect, and how CBP is ‘safeguard(ing) our national security ... while simultaneously protecting the civil rights and liberties of everyone.’”

The senator asked CPB to provide more details by Jan. 14.