Japan will not join a U.S.-led security mission to protect merchant vessels passing through key Middle Eastern waterways, but will consider deploying its naval force independently, the Yomiuri newspaper reported Tuesday.

Though the United States is Japan's most important ally, Tokyo has fostered economic ties with Iran, and Japanese firms had been major buyers of Iranian oil until U.S. sanctions forced them to find other suppliers.

Citing unidentified government sources, the Yomiuri said Japan was considering a plan to send its Maritime Self-Defense Force on information-gathering missions in the areas around the Strait of Hormuz and Bab al-Mandab shipping lane between Yemen, Djibouti and Eritrea.