Three major U.S. cities are protesting an anti-gay bill approved last week by North Carolina lawmakers by limiting travel to the state.

San Francisco Mayor Ed Lee announced on Friday that he was barring city employees from non-essential travel to the state.

San Francisco “will not subsidize legally sanctioned discrimination,” Lee said in a statement.

On Monday, New York Mayor Bill De Blasio and Seattle Mayor Ed Murray, who is openly gay, followed suit.

“It is my hope for our nation that we do not allow issues of discrimination to divide us,” Murray said. “Our union is only made stronger when all Americans are treated equitably.”

North Carolina lawmakers approved and Republican Governor Pat McCrory signed into law House Bill 2 during a one-day special session at a cost of $42,000 to taxpayers. The legislation was a response to passage of an LGBT protections ordinance in Charlotte set to take effect on April 1. House Bill 2 prohibits any city, town or municipality from enacting measures that prohibit discrimination based on sexual orientation or gender identity and bars students attending public institutions from using the bathroom that does not conform to their gender at birth.