Japan's Prime Minister Shinzo Abe has condemned the suspected attack on a Japanese-operated tanker near the Strait of Hormuz this week as a threat to safe maritime navigation.

Abe, speaking to reporters Friday, says: "Japan adamantly condemns the act that threatened a Japanese ship, no matter who attacked."

The tanker, Kokuka Courageous, was attacked by what its crewmembers described as "flying objects" near the Strait of Hormuz, carrying methanol to Singapore and Thailand. All 21 Filipino sailors were safely evacuated.

Abe urged "all related countries" to avoid an accidental confrontation and refrain from any action that may escalate tensions. He pledged to help de-escalate tensions in the region.

Abe made the remarks after telephone calls with U.S. President Donald Trump, briefing him on his Iran visit this week, without elaborating. He pledged to keep cooperating with Trump.