MANILA — A radio host who had been a prominent critic of President Ferdinand Marcos Jr. of the Philippines was fatally shot in his car during an ambush near his home, the authorities said on Tuesday.

The broadcaster, Percival Mabasa, was killed on Monday night in Metro Manila, by two men on motorcycles who later escaped, said Brig. Gen. Roderick Augustus Alba, a spokesman for Philippine National Police. The shooting occurred in the suburb of Las Pinas, outside the gated community where Mr. Mabasa lived.