BEIJING — China rejected suggestions that its fighter jets flew dangerously close to an American surveillance aircraft and instead accused the United States on Thursday of threatening its security by regularly sending such flights near the Chinese coast.

A spokesman for the Chinese Ministry of Foreign Affairs made the counteraccusations after the Pentagon raised concerns about a close encounter on Tuesday with an American surveillance plane, which the United States said was approached by two Chinese jets that flew within 50 feet of it.

“American military vessels and aircraft frequently engage in surveillance in close proximity to China’s coastal waters, and this constitutes a grave threat to China’s security on land and sea,” the spokesman for the ministry, Hong Lei, told a daily news briefing in Beijing. “China requests that the United States immediately halt this kind of close-proximity surveillance, thereby avoiding the recurrence of such incidents.”