U.S. Immigration and Customs Enforcement has been ordered to temporarily stop conducting vehicle stops in the wake of two deadly shootings in Texas and Maine, sources told ABC News.

Homeland Security Secretary Markwayne Mullin gave the directive, a law enforcement source told ABC News, after he spoke with Sen. Susan Collins, R-Maine, who said she urged Mullin to “cease all non-urgent vehicle stops.”

In an email sent to ICE deportation officers, a senior ICE official wrote that the vehicle stops are paused “immediately,” according to the email reviewed by ABC News.

“All personnel are instructed to prioritize other existing operational methods, outside of vehicle stops, to conduct immigration enforcement activities,” the official wrote.

In most cases, ICE officers will stop a target on the street once they leave their house or office, but ICE will still use vehicle stops in cases involving the most dangerous targets, according to a source.

Multiple sources said the pause is temporary and that ICE officers will receive new training on vehicle stops.

Additionally, one source said that ICE officers can conduct some vehicle stops during the pause but only in the presence of a local law enforcement officer trained to make vehicle stops that partners with ICE under the agency’s 287(g) program.

A Department of Homeland Security spokesperson told ABC News that the agency won’t “disclose or discuss law enforcement tactics,” but added that it’s “always evaluating our procedures to keep our officers safe and criminals off our streets.”

In an interview on Fox News, border czar Tom Homan confirmed the temporary pause and said DHS will review the past few incidents. 

“It is not a policy change, it is a temporary pause,” Homan said. “Look – last couple of shootings, ICE leadership along with DHS wants to look at these last couple incidents and look, is there something that could have been done better? Is there any training that could be improved? Or simply is ICE doing their job and bad things happen when people don’t comply with law enforcement officers? I think it going to be a short pause and I am confident that ICE is well trained in vehicle stops and you’re going to see us keep moving forward.”

On Monday, 26-year-old Johan Sebastián Guerrero was fatally shot by an ICE agent in Biddeford, Maine, after agents tried to stop the car he was driving, according to Sen. Angus King, I-Maine.

Guerrero, a Colombian national, was not the target of the operation and ICE agents had been given a final order for another man they were targeting to be removed from the U.S., King told ABC News.

An ICE spokesperson said that the agency was “conducting targeted surveillance on the last known address of an illegal alien with a final order of removal,” and when an “illegal alien departed the residence in a vehicle,” ICE agents “attempted to conduct a vehicle stop.”

“The vehicle attempted to flee the scene and fearing for public safety an officer discharged his weapon,” ICE said.

The Maine Attorney General’s Office said “the suspect attempted to flee in the vehicle in the direction of the officer and was fatally shot.”

Witness Daniel Boucher told ABC News that he watched agents pull the shooting victim from his car and put him on the ground.

“I heard the young man say, ‘I tried to stop.’ I clearly heard him say that,” said Boucher, adding that he overheard one of the ICE agents allegedly say the driver tried to run him over.