South Korea recovers part of rocket used in North's failed satellite launch

South Korea has recovered from the sea part of a rocket used in North Korea's failed attempt to launch its first military satellite last month, the Joint Chiefs of Staff said on Friday.

The debris was salvaged on Thursday evening, the military said, adding that they continued to search for additional objects from what the North claimed was a space launch vehicle.

On May 31, North Korea tried to launch its first spy satellite, but the flight ended in failure with the booster and payload plunging into the sea.

South Korea found debris off its west coast soon after the launch, and began a salvage operation in the hopes of studying the new rocket.

Photographs released by the South Korean military showed a large cylindrical object marked "Chonma," meaning a winged horse in Korean. North Korea had said the rocket was named "Chollima-1."

"The salvaged object will be thoroughly analysed by expert organisations, including the Agency for Defense Development," the military said in a statement.

South Korea's Defence Minister Lee Jong-sup had said the debris appeared to be the second stage of the rocket, and that the military would continue searching for the payload and the third stage.

Chinese warships had also conducted salvage operations in waters where the North Korean rocket crashed, South Korea said on Monday. It was not immediately clear whether the Chinese military was continuing its search.

Seoul and Washington have condemned the launch as a provocation and violation of UN Security Council resolutions banning the North's use of ballistic missile technology.

Pyongyang said it was exercising its right to space development to counter what it described as US "aggression" and vowed to stage another launch soon.

On Friday, a US submarine arrived in South Korea in a show of force, a day after North Korea fired two short-range missiles off its east coast, warning of an "inevitable" response to military drills staged by South Korean and US troops.