MANILA (Reuters) - 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.

Philippines Vice President Leni Robredo listens to a reporter's question during a news conference following her resignation from her post in President Rodrigo Duterte's cabinet, at the Quezon City Reception House, Metro Manila, Philippines December 5, 2016. REUTERS/Ezra Acayan

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.

Robredo renewed her warning of a plot taking shape to remove her from the number two post and said the instruction from Duterte was tantamount to being sacked.

“If you are not being allowed to attend cabinet meetings anymore, what does that mean?” she said at a news conference.

“I will be an opposition leader. I will oppose policies that will be detrimental to the people.”

Those includes the death penalty, lowering the age of criminal liability and alleged extrajudicial killings as part of the crackdown on drugs, which has killed more than 2,000 people.

Duterte accepted Robredo’s resignation as housing secretary “with a heavy heart”, his spokesman Ernesto Abella said.

Robredo, 52, a former lawyer and social activist, won the vice presidential election in May by a narrow margin, defeating Ferdinand Marcos Jr, the son and namesake of the late dictator overthrown in a 1986 revolt.

Marcos, better known by his nickname “Bongbong”, has appealed to a tribunal of the Supreme Court for a recount, which Robredo said she was confident of winning.

Robredo did not give details of the alleged plot to “steal” the vice presidency, but said Marcos accompanying Duterte on an official visit to China in October was telling.

“In China, the president took Bongbong Marcos and even introduced him as the vice president,” she said.

Marcos’s lawyer, Vic Rodriguez, issued a statement saying Robredo’s resignation was “long overdue given her very obvious adversarial attitude”.

He described Robredo’s claim of a plot to unseat her as hypocritical.

“The vice presidency has indeed been stolen, and it was stolen by no less than Mrs Robredo,” Rodriguez said.