China and the Philippines said on Friday they launched rescue operations after receiving reports of a sinking cargo ship near the Scarborough Shoal in the South China Sea that was carrying 21 Philippine crew members.

Scarborough Shoal is one of Asia's most contested maritime features and a frequent flashpoint in disputes, particularly between China and the Philippines, over sovereignty and fishing rights.

The Chinese military said 17 crew members were rescued and two of them later died, after a report around 1:30 a.m. on Friday (1730 GMT on Thursday) that a foreign cargo vessel had capsized in waters near the shoal.

It dispatched aircraft to conduct searches and the Chinese Coast Guard sent two vessels for rescue efforts.

One person was receiving emergency medical treatment, it said, adding that China's maritime authorities were organising additional rescue forces to head to the area.

The Philippine Coast Guard said it deployed two vessels and two aircraft to rescue the Philippine crew from a Singaporean-flagged cargo vessel loaded with iron ore that was en route to the southern Chinese city of Yangjiang.

"The PCG Command Center acquired information from the Hong Kong Maritime Rescue Coordination Centre that 10 of the 21 Filipino crew members were rescued by a passing China Coast Guard vessel," it said.

The Maritime and Port Authority of Singapore confirmed that the bulk carrier, "Devon Bay", had sunk in the South China Sea while en route to Yangjiang.

"As the vessel’s flag state, MPA is in contact with the ship owner and relevant search and rescue authorities, and is providing support as required," it said, adding that it will investigate the incident.

Underlining the Scarborough Shoal's disputed status, China's military said on Tuesday it had organized naval and air force units to repel a Philippine government aircraft that it accused of "illegally intruding" into airspace over the atoll.

Both China and the Philippines claim the Scarborough Shoal, but sovereignty remains unresolved. China took control in 2012 after a standoff and has since stationed its coast guard and fishing vessels there.

A 2016 ruling by the Permanent Court of Arbitration in The Hague invalidated China's sweeping claims in the South China Sea and declared its blockade illegal, affirming the shoal as a traditional fishing ground for countries like the Philippines and Vietnam. China rejected the ruling.

China's claims overlap with the exclusive economic zones of Brunei, Indonesia, Malaysia, the Philippines and Vietnam.

-Reporting by Beijing Newsroom Karen Lema in Manila and Jun Yuan Yong in Singapore; editing by Raju Gopalakrishnan, Michael Perry and Mark Heinrich/Reuters