The government has put South Korean ships fishing in the Persian Gulf on high alert following terrorist threats by Islamist militants.

The Ministry of Maritime Affairs and Fisheries said Wednesday that it issued the alert after receiving intelligence that South Korean vessels are included in a group of ships that Islamist militants have threatened to attack.

The ministry has put in place a system that will allow swift communication between the nine vessels currently operating in the Persian Gulf with the Seoul government.

The purported threat comes as Seoul prepares to send the first batch of 3,000 additional troops to the Kurdish region of northeastern Iraq next month. They will be joined there by about 600 Korean military medics and engineers already operating in the country's south.

The deployment will make South Korea the biggest contributor of coalition forces in Iraq after the United States and Britain.