A dramatic increase in immigration enforcement at US airports has reportedly placed the airline industry at odds with the Trump administration as workers decline to help federal officials arrest their targets – many of whom have pending applications for visas, asylum or green cards.

Immigration and Customs Enforcement (ICE) and the Transportation Security Administration (TSA) – both part of the Department of Homeland Security (DHS) – have expanded their collaboration to make as many as three dozen daily arrests at US airports last month, the Wall Street Journal reported.

Some of the people who have been taken into federal immigration custody include a former au pair, an asylum seeker with sickle cell anemia who uses a wheelchair, and women who are married to US citizens and in the process of applying for lawful permanent residency, according to the New York Times.

“It’s not people with criminal records,” said Ghassan Shamieh, a San Francisco-based immigration lawyer who had four clients detained at airports over 10 days. “You are talking about people with legitimate pending applications.”

The latest crackdown represents another policy shift for the DHS, which has generally avoided immigration enforcement at airports so as not to disrupt domestic travel. But with a goal of 2,000 daily immigration arrests, ICE has started detaining people – many of whom have overstayed visas after coming to the US legally and have pending applications for immigration relief – in public places far from security checkpoints, whether at ticket counters or near gates.

“This administration is working diligently to ensure that aliens in our country illegally can no longer fly unless it is out of our country to self-deport,” a DHS spokesperson told the New York Times.

At one point, in Dallas, a federal agent went so far as to try to board a plane in search of a target. But the Southwest Airlines gate agent reportedly refused to allow the officer to do so without a warrant signed by a judge, and airline employees blocked ICE from seeing a computer screen while passengers were boarding.

Southwest told the Wall Street Journal that it follows the law and has protocols “to ensure appropriate legal documentation is presented by law enforcement personnel before any information about customers is shared”.

Still, hundreds of immigration arrests have already taken place at airports since the TSA and ICE began cooperating with one another last year. Members of the airline industry met with DHS in July to discuss their discomfort with the policy change.

On top of the immigrants being detained, experts have raised concerns that the tense encounters could lead to escalation and unsafe conditions for bystanders or airline employees.

“The actions that federal enforcement authorities have taken in our workplaces have raised glaring workplace, safety and legal concerns for flight attendants,” Sara Nelson, international president of the Association of Flight Attendants, wrote in a letter to carriers in March.