TOKYO (KYODO) - Japan may send vessels to patrol off Yemen rather than joining a US-led coalition to protect shipping in the Strait of Hormuz amid heightened tensions with Iran, government sources said on Thursday (Aug 8).

The administration of Prime Minister Shinzo Abe is reluctant to send the Maritime Self-Defence Force to the strait, a key sea lane through which around a fifth of the world's oil passes, out of concern that doing so could hurt Tokyo's friendly ties with Teheran.

But it is under mounting pressure from Washington to participate in the US effort, dubbed Operation Sentinel, with Pentagon chief Mark Esper earlier this week urging Japan to "strongly consider" it.

As a compromise, Japan is considering sending MSDF destroyers and P-3C Orion surveillance planes to the Bab el-Mandeb Strait between Yemen and the Horn of Africa, the sources said.

"We can't just do nothing," a senior Abe administration official said.

The mission would likely be taken up by forces already engaged in anti-piracy operations off Somalia.

The Japanese vessels would not be part of the US-led coalition, though the area of operations would overlap.

Mr Abe hopes to discuss the issue with US President Donald Trump when they meet later this month in France on the sidelines of a Group of Seven summit, according to the sources, with a final decision dependent on how other US allies opt to proceed.

Britain and Israel have announced they will participate in the coalition, but Germany has declined.

At present, officials in the Abe administration think such a mission would be possible under existing legislation.

SDF activities overseas are restricted under the war-renouncing Constitution.