“Regarding the Chinese vessels, a salvage operation is currently being carried out at a point 200km (124 miles) west of Eocheongdo, and the waters are open sea,” Lee Sung-jun, spokesman for South Korea’s Joint Chiefs of Staff, said at a regular briefing on Monday.

“We understand that some Chinese warships are active in that open sea,” Lee said, adding that there were “no disturbances” around the Chinese activity that required any response from the South Korean side.

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His comments came after NK News, a Seoul-based website monitoring North Korea, reported on Friday that Chinese vessels have intensified patrols in the Yellow Sea where debris from North Korea’s failed satellite launch fell.

On May 31, North Korea attempted to launch its first spy satellite into space, but it ended in failure with the booster and payload plunging into the sea. It has vowed to conduct another satellite launch soon.