Japan may assign two Self-Defense Force vessels to help protect Middle East waterways as part of a dispatch plan under consideration, according to a government source .

Chief Cabinet Secretary Yoshihide Suga said Friday the Gulf of Oman, the northern part of the Arabian Sea and the eastern part of the Bab el-Mandeb strait, connecting the Red Sea and the Gulf of Aden, are potential locations for the dispatch.

An SDF ship currently in the Gulf of Aden off the coast of Yemen to guard against pirates would be sent on the new mission, joined by another ship to be dispatched from Japan, the source said Saturday.

The Defense Ministry does not want to send more than two ships to the Middle East amid the growing North Korean missile threat, according to the source.

The vessels will be allowed to use force to defend Japanese merchant vessels under attack, the source said.

Japan initially sent two vessels to the Gulf of Aden in 2009. It ordered one home in 2016 as pirate incidents decreased.

The government also said Friday it would not join a U.S.-led coalition to guard shipments traveling through the Strait of Hormuz amid tensions involving Iran.

The United States has formed a coalition to protect the Middle Eastern sea lanes following attacks on two oil tankers, one operated by a Japanese shipping firm, near the strait in June, for which Washington blamed on Iran.

Japan has refrained from making a decision on the U.S. initiative partly because it does not want to damage its traditionally friendly relations with Iran.

Sending SDF personnel overseas is a sensitive issue in Japan as an entanglement in a foreign conflict could violate the country's war-renouncing Constitution.