The group stormed the CK BlueBell cargo ship and assaulted crew before taking their belongings, MirrorOnline reported. The pirates have made off with up to £10,394 in cash as well as the sailors’ clothes. Some of the crew have minor injuries, according to local reports.
The armed pirates spent up to 30 minutes on the vessel which was headed to Brazil, KBS World Radio reported.
According to Yonhap News Agency, a South Korean Ministry of Maritime Affairs and Fisheries official said: “Ordinary freighters navigate at a speed below 15 knots.
“But a speed boat operated by the pirates approached the freighter at a speed above 20 knots.
“Afterwards, seven weapons-wielding pirates got on board and assaulted the sailors for about 30 minutes.”
READ MORE: North Korea: Kim makes ‘RAPID’ improvements to nuclear sites
Piracy has fallen in the busy sea lane that runs past Singapore, Malaysia and Indonesia in recent years amid heavier policing.
The cargo ship, which is heading to Incheon city from Brazil, resumed its scheduled route after the attack.
The Singapore Strait is located in-between Singapore and Batam.
The strait is incredibly busy as it provides the deepwater passage to the Port of Singapore.
A total of 2,000 merchant ships traverse the waters on a daily basis.
The waterway which leads on to the Strait of Malacca border Malaysia has been prone to piracy for years.
There have recently been coordinated patrols by Indonesia, Malaysia, Thailand, and Singapore along with increased security on vessels.
The measures sparked a sharp downturn in piracy.