WASHINGTON (Reuters) - The State Department said on Monday the United States is concerned about extrajudicial killings in the Philippines, where officials say more than 400 suspected drug dealers have been killed by police since President Rodrigo Duterte took over.

State Department spokeswoman Elizabeth Trudeau said at a news briefing that the United States is urging the Philippines to observe the rule of law in detaining suspects.

(Reporting by Ruthy Munoz; Editing by Steve Orlofsky)