WASHINGTON (Reuters) - The United States is struggling to win support from its allies for an initiative to tighten controls on vital oil shipping routes in the Middle East because of fears they would increase tensions with Iran, Reuters reported.

Washington proposed on July 9 to strengthen efforts to protect strategic waters off Iran and Yemen, where Americans hold Tehran and its proxies responsible for attacks on tankers, while Iran denies the charges.

But with Washington's allies reluctant to commit new weapons or combat forces, a senior Pentagon official told Reuters on Thursday the US goal was not to form a military alliance but to launch a warning in the region to deter attacks on commercial shipping.

Because of fears of confrontation, any intervention by Washington's allies is likely to be limited to naval and gear personnel already located near the Strait of Hormuz in the Gulf and the Bab al-Mandab strait in the Red Sea, Gulf and Gulf security sources said.

The developments came after an increase in tension on Thursday after the Iranian Revolutionary Guard said it had detained a foreign tanker smuggling fuel. A US commander in the region said the United States was working "diligently" to ensure free passage of ships in and around the Strait of Hormuz.

Trump pulled out of Iran's nuclear deal in May 2018 (Reuters)

Tension and withdrawal
Tensions have risen since US President Donald Trump pulled out last year from a nuclear deal signed in 2015 that Iran agreed to curtail its nuclear program, in return for easing sanctions crippling its economy.

France, Britain and Germany - one of the signatories to the pact along with Russia and China - are trying to save it from collapse and defuse tensions.

"The Americans want to form a coalition of those willing to counter any future attacks," said a Western diplomat. "Nobody wants to be on this collision course and within an American campaign against Iran."

Catherine Wilberger, one of the top policy officials at the Pentagon, spoke of these fears and potential misunderstandings and told Reuters in an interview that the new initiative was "not about the military confrontation."

Under Washington's proposal, the United States will provide coordination ships and lead surveillance efforts, while allies patrol nearby waters and accompany commercial vessels flying their flags.

Iran said foreign powers should leave the issue of securing shipping lines to Tehran and other countries in the region.

A French official said that Paris, which has a naval base in the UAE, has no intention of escorting the ships and believes that the US plan will negatively affect the process of easing tensions because Tehran will see it as hostile to it.

For his part, said a British security source that the escort of each merchant ship is not applicable, a view shared by several other countries.

US patrols in Gulf (Reuters)

Alliances and fears
Meanwhile, a senior Western official based in Beijing said China "can not" join a naval alliance. A South Korean official said Washington had not yet made any formal request.

Any decision by Japan to join such an initiative is likely to fuel a split in Japanese public opinion about sending troops abroad. The Japanese army has not fought abroad since World War II.

Saudi Arabia and the UAE are already watching the coast of Yemen, leading an alliance fighting the Houthi group allied to Iran. But the UAE has said it will reduce its presence there.

A Saudi military official was asked about the role Riyadh could play in the US initiative, saying the role of the Saudi-led coalition over the past few years in the Red Sea would be part of the war in Yemen, including escorting and securing commercial vessels. The United States does not want to do so alone.

"There is enough resources in the region now to do the job, and the Americans want an international character for these efforts and they do not want to bear the financial burden," said one Gulf exporter.

Technical and financial aspects, such as fuel, storage and maintenance costs, must be resolved before countries agree to participate, the source added.

The burden of surveillance will be mainly on the United States, which has been protecting shipping corridors in the region for decades with its fifth fleet based in Bahrain. It is also leading the joint naval force, a 33-nation naval alliance charged with security operations and fighting piracy in the region.