Washington (CNN) Michael Knowles, president of a local union that represents US asylum officers, denounced the Trump administration's asylum policies during a House hearing Tuesday, calling them "egregious" and "illegal."

"These policies are blatantly illegal, they are immoral, and indeed are the basis for some egregious human rights violations by our own country," Knowles testified a hearing on the administration's policy of returning migrants to wait in Mexico as their cases move through the US immigration court system.

Roughly 60,000 migrants have been returned to Mexico under the program.

Earlier this year, the union asked a federal court to end the policy , officially called Migrant Protection Protocols, in a court filing -- one of court briefs filed in opposition to the administration's refugee and asylum policies.

"I don't know a single asylum office in the country, and I speak to them all over the country, who believes it is a good policy," Knowles said Tuesday.

Most asylum officers believe the program is illegal and "places them feeling that they are complicit in human rights abuse," Knowles added.

Then-acting US Citizenship and Immigration Services Director Ken Cuccinelli backed the policy following the union's filing against the program in June. "This lawsuit is an attempt by the union to score short-term political points," Cuccinelli said in a series of tweets. "MPP protects both the vulnerable, while they wait for their hearing, and our asylum system from choking on meritless claims. THAT is what protection officers signed up for."

The Department of Homeland Security cited US law in defending the program in a statement. "We appreciate the opportunity to clarify a federal statute enacted on a bipartisan basis over 20 years ago. This section of law clearly states that aliens arriving from a contiguous territory may be returned to that territory pending their immigration hearing. Strongly held personal political biases are no excuse for ignoring the law," a spokesperson said.

Witnesses at Tuesday's hearing, which included lawyers and a physician, recounted harrowing stories of kidnapping, sexual assault, and torture experienced by these migrants as they await their court date in the US.

The so-called "Remain-in-Mexico" policy was initiated at the San Ysidro port of entry in San Diego at the start of the year and has since expanded to other parts of the border. Immigrant advocates immediately challenged the program, but the 9th US Circuit Court of Appeals has allowed it to proceed for the time being

Since then, the administration has erected tent facilities in Laredo and Brownsville, Texas, for immigration proceedings. The judges are not at the tent facility but preside by teleconference from other immigration courts several miles away.

The policy is one of many rolled out by the administration to curb the flow of asylum seekers to the southern border, including proposals to add a charge to asylum applications and deny work permits to some migrants seeking asylum.

The administration is also preparing to implement an agreement with Guatemala that bars migrants from seeking asylum in the US, with some exceptions, and allows the US to instead send asylum seekers to Guatemala.

Knowles said that asylum officers will be trained Tuesday on how cases will be handled for asylum seekers who will be transported to Guatemala to have their cases heard there.

"The morale under this administration has plummeted, not because of people's political views, but because of the way that we have been treated and the way that we have been required to carry out very questionable programs," Knowles said of the asylum workforce.

"We have not been consulted, either the union or the workforce, on the advisability of various methodologies or procedures," he added. "We're just told to carry it out, and, 'If you don't like it, you can go work somewhere else.'"