SEATTLE — A Customs and Border Protection memo obtained by The Associated Press confirms that bus companies such as Greyhound do not have to allow Border Patrol agents on board to conduct routine checks for immigrants living in the country illegally. 

That's contrary to Greyhound's long insistence that it has no choice but to let the agents on board. 

Immigrant rights activists say the memo gives them additional leverage as they pressure Greyhound to stop allowing sweeps.

Greyhound told the AP it appreciated the Border Patrol “clarifying” its policy. It declined to say whether it would prohibit agents from boarding its buses. 

RELATED: Maryland man accused in Greyhound bus shooting in California that killed 1

RELATED: 32-year-old man dies while in custody of Border Patrol agents

Border Patrol Bus Checks Seattle
In this Thursday, Feb. 13, 2020 photo, a worker speaks with Customs and Border Protection agent seeking to board a Greyhound bus headed for Portland.