United States authorities are investigating reports that several Sikh asylum seekers were made to take off their turbans at the country’s border with Mexico, the BBC reported on Thursday.

The allegations emerged in June, according to ABC News.

The investigation began after human rights activists said that nearly 50 Sikh migrants had to take off the headgear, wearing which is an essential religious practice in Sikhism. Record numbers of migrants from India have been detained at the US-Mexico border in recent months, according to the BBC.

In a letter sent to the US Customs and Border Protection commissioner on August 1, the American Civil Liberties Union contended that confiscating the turbans “blatantly violate federal law”. The action also violates the non-discrimination policies of the Customs and Border Protection force, the letter stated.

The American Civil Liberties Union has documented complaints of 47 Sikhs who were seeking asylum in Arizona state. The turbans of the complainants were taken away and have not been returned in two months.

“We take allegations of this nature very seriously,” Customs and Border Protection Commissioner Chris Magnus told ABC News on Wednesday. “Our expectation is that CBP employees treat all migrants we encounter with respect. An internal investigation has been opened to address this matter.”

Volunteers of refugee resettlement organisation International Rescue Committee of Arizona have collected turbans from the local Sikh community to provide headgears to the asylum seekers. “Unfortunately, this is not a long-term solution because of the sheer number of turbans needed,” the American Civil Liberties Union said, according to ABC News.