In a move that could heighten pressure on Japan, Australian Prime Minister Scott Morrison announced Wednesday that his country will join the U.S.-led mission to protect shipping through the Strait of Hormuz amid ongoing tensions with Iran, albeit under Australia's operational control.

Morrison said Australia would send a "modest" contribution — including a frigate, a P8 maritime surveillance aircraft and support staff — to the mission, which will also involve British and Bahraini forces.

"Our contribution will be limited in scope and it will be time-bound," Morrison said, expressing concern about security incidents in the vital shipping lane over the past few months.