Philippines Vice President Leni Robredo resigned from the cabinet on Monday but vowed to lead the opposition and challenge the policies of President Rodrigo Duterte, including his deadly war on drugs and moves to reinstate the death penalty.

Robredo, who will remain vice president, had clashed frequently with Duterte and decided to resign from her ministerial role after being instructed via a text message to stay away from his cabinet meetings.

She was elected vice president in May in a separate contest and was not Duterte’s running mate.