Lebanese authorities have arrested 16 people in an investigation into the Beirut port warehouse explosion, state news agency NNA said on Thursday, and a judicial source and local media said the port’s general manager was among those being held.

NNA did not name the individuals, but quoted Judge Fadi Akiki, a government representative at the military court, as saying authorities had so far questioned more than 18 port and Customs officials and others involved in maintenance work at the warehouse...