SINGAPORE - The pirate attack on a South Korean-flagged cargo ship did not take place in Singapore waters, the Maritime and Port Authority of Singapore (MPA) said on Monday (July 22).

Pirates attacked the ship CK Bluebell early on Monday, stealing thousands of dollars in cash and even the sailors' shoes, South Korean authorities said.

In response to queries from The Straits Times, the MPA said it was informed "by the Korea Coast Guard that it took place in the South China Sea near Anambas Islands. It did not take place in Singapore waters".

The Anambas Islands are part of Indonesia's Riau Islands province.

Two people sustained minor injuries when seven pirates boarded the ship and made off with US$13,000 (S$17,690) and belongings including mobile phones, clothes and shoes from the 22-strong crew, officials from South Korea's Ministry of Oceans and Fisheries said, according to Reuters.

Yonhap news agency earlier reported that the incident took place near the Singapore Strait, a busy sea lane that runs past Singapore, Malaysia and Indonesia.

Piracy in the strategic shipping route has been less common in recent years due to heavier policing.

The dry bulk vessel CK Bluebell set sail from its anchorage off Singapore late on Saturday afternoon, heading northeast for South Korea's Incheon port, according to Refinitiv Eikon ship tracking data.

South Korean officials said the ship was sailing normally after the robbery, reported Reuters.

This month, China's Ministry of Transport raised its security recommendation for Chinese vessels in the nearby Malacca Strait, between the Malay Peninsula and the Indonesian island of Sumatra.

A Chinese official declined to specify the reason for the new security level, saying only that the decision was the result of comprehensive research taking all factors into account.