BOSTON (AP) — Peter Pan Bus Lines, a major Northeast carrier, will continue to allow federal immigration officials on its buses to conduct routine checks for immigrants living in the country illegally, saying it could help stem human trafficking, the company said this week.

Peter Pan, based in Springfield, Massachusetts, “has always and will continue to cooperate with law enforcement,” Christopher Crean, vice president of safety and security, said Monday.

Some of the bus line's rivals have revised or are reviewing their longstanding policies. But Peter Pan remains concerned about the potential for child trafficking on its buses, Crean said.

The company is a member of Truckers Against Trafficking, an industry group formed to fight human trafficking, as well as a similar regional effort by businesses in western Massachusetts.

“It would be contradictory for us not to allow them on, especially if it could result in stopping a young child from being trafficked,” Crean said. “I don’t think we’ll look at this issue any different now, whether it's Border Patrol or other law enforcement.”

The company wasn't able to provide an estimate for how many times in recent years immigration officials have boarded the company's buses.

But Crean said it was “not frequent,” given the company's routes are concentrated on transit between major Northeast cities including Boston, New York, Philadelphia and Washington.

Greyhound, the nation’s largest bus company, said last month it would stop allowing Border Patrol agents to board its buses without a warrant.

New Hampshire-based Concord Coach Lines, which connects communities in New Hampshire and Maine with Boston and New York City, followed suit Friday.

The announcements came after The Associated Press reported on a U.S. Customs and Border Protection memo saying its agents can’t board private buses without the consent of the bus company.

Greyhound and other companies had previously insisted they had no choice but to allow the immigration checks even if they didn’t like them.

The American Civil Liberties Union has been calling on motorcoach companies to allow Border Patrol agents onto their buses only if they have a warrant, noting that the agency has been stepping up enforcement beyond the country's immediate borders in recent years.

“Peter Pan Bus Lines is in the business of transporting its passengers safely from place to place,” the civil rights group's New Hampshire, Maine and Vermont chapters said in a joint letter to the company in 2018. "It should not be in the business of subjecting its passengers to intimidating interrogations, suspicionless searches, warrantless arrests, and the threat of deportation.

Boston is among the sanctuary cities where border patrol units, some of which have tactical training, were recently deployed to bolster immigration enforcement efforts.