WASHINGTON (Kyodo) -- U.S. President Donald Trump's administration is planning to form an international maritime surveillance mission involving 55 vessels in a key waterway off Iran in November, a source familiar with the plan said Thursday.
The plan came to light amid heightened tensions between the United States and Iran following recent attacks on major oil facilities in Saudi Arabia, an incident Washington has blamed on Tehran.
But the administration is likely to face difficulties in implementing the plan because only five countries -- Australia, Bahrain, Britain, Saudi Arabia and the United Arab Emirates -- have agreed to join the U.S.-led coalition aimed at ensuring safety in the Strait of Hormuz at the mouth of the Persian Gulf.
The United Arab Emirates became the latest country to announce its participation in the mission, known as the International Maritime Security Construct, according to the state-run Emirates News Agency.
"The UAE's accession to the alliance comes in support of regional and international efforts to deter threats to maritime navigation and global trade, and in order to secure the flow of energy supplies to the global economy and contribute to the maintenance of international peace and security," the news agency said Thursday.
While the United States has lobbied other countries to join the coalition to increase pressure on Iran, Japan has expressed reservations about participating.
According to the source, the United States presented the surveillance plan to allies and partner countries in a meeting Monday in Bahrain.
Representatives from 28 countries attended the meeting aboard a British navy ship, with Japan believed to have participated.
France and Germany, key U.S. allies, did not take part in the meeting in an apparent effort to maintain a distance from Trump, who withdrew the United States from a 2015 international deal to curb Iran's nuclear program.
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 its Self-Defense Forces overseas is a sensitive issue in Japan, as entanglement in a foreign conflict could violate the country's war-renouncing Constitution.
Stability and safe passage in the Strait of Hormuz is vital for Japan, which relies on the Middle East for 90 percent of its crude oil.
In Monday's meeting, Finland, Kuwait and Latvia said they were considering sending personnel to the U.S. coalition headquarters in Bahrain, according to the source.
The United States launched the coalition initiative after two oil tankers, including one operated by a Japanese company, were attacked near the Strait of Hormuz in June.
Washington has put the blame on Tehran, which has denied responsibility.