PHNOM PENH, Cambodia — Vietnamese President To Lam was confirmed Saturday as the new chief of the Communist Party after his predecessor died July 19.

Lam will be the general secretary of the Communist Party of Vietnam, the country’s most powerful political role, state media said. It was unclear if Lam will stay in his role as president.

The previous general secretary, Nguyen Phu Trong, dominated Vietnamese politics since he became party chief in 2011. He was elected to a third term as…