A fourth bus transporting migrants arrived Tuesday in Los Angeles from Texas, Mayor Karen Bass’s office announced. 

“One bus with migrants on board from Texas arrived around 6:30 PM PT today at Union Station,” the statement said. “The City has continued to work with City Departments, the County, and a coalition of nonprofit organizations, in addition to our faith partners, to execute a plan set in place earlier this year. As we have before, when we became aware of the bus yesterday, we activated our plan.”

Texas Gov. Greg Abbott (R) has previously sent three buses of migrants from Texas immigration facilities to Los Angeles, a scheme Abbott said is meant to protest undocumented immigrant protections in the city.

“Los Angeles is a major city that migrants seek to go to, particularly now that its city leaders approved its self-declared sanctuary city status,” Abbott said in a release last month.

“Our border communities are on the frontlines of President Biden’s border crisis, and Texas will continue providing this much-needed relief until he steps up to do his job and secure the border,” he wrote.

The Los Angeles mayor’s office said each bus came with about a day’s notice, requiring a significant partnership with local nonprofits to help the migrants.

Abbott has sent more than 20,000 migrants around the country on buses, mostly to so-called sanctuary cities including Denver, Chicago, Philadelphia and Washington, D.C.