SEOUL, July 10 (Reuters) - North Korea accused the United States on Monday of violating its airspace by conducting surveillance flights and warned that, while Pyongyang was exercising restraint, such flights may be shot down.

Provocative military actions by the United States were bringing the Korean peninsula closer to a nuclear conflict, said an unnamed spokesperson of North Korea's Ministry of National Defence in a statement carried by the official KCNA news agency.

The report also cited the use of U.S. reconnaissance planes and drones and said Washington was escalating tensions by sending a nuclear submarine near the peninsula.

"There is no guarantee that such a shocking accident as the downing of the U.S. Air Force strategic reconnaissance plane will not happen" in waters east of Korea, the spokesperson said.

The statement cited past incidents of the North shooting down or intercepting U.S. aircraft at the border with South Korea and off the coast. North Korea has often complained about U.S. surveillance flights near the peninsula.

There was no immediate response from the U.S. military stationed in South Korea to a request for comment.