Greyhound said Friday it would prohibit U.S. Customs and Border Protection agents without a warrant from boarding its buses to conduct immigration checks as bus companies continue to face pressure from civil rights advocates over the practice.

The announcement comes after an Associated Press report said a Jan. 28 Border Patrol memo contradicted Greyhound's stance that it had to allow the agents on its buses under federal law.

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The company has maintained it didn't agree with the checks but had no choice but to comply.

The memo addressed to all chief patrol agents and signed by then-Border Patrol Chief Carla Provost before her retirement said agents can't board private buses without consent from bus companies.

“When transportation checks occur on a bus at non-checkpoint locations, the agent must demonstrate that he or she gained access to the bus with the consent of the company’s owner or one of the company’s employees,” the memo states.

Border agents regularly climb onto buses within 100 miles of the border to ask passengers about their immigration status. Some have been captured on video, prompting outrage from immigration advocate groups.

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Civil rights organizations argue the checks are discriminatory and that passengers are routinely profiled under the Trump administration. Greyhound faces a lawsuit in California over the checks, which some claim violate consumer protection laws.

The company said it would provide training to its drivers and bus station employees about the new policy, along with stickers to be placed on buses saying it does not consent to searches.

The Associated Press contributed to this report.