The United States and more than two dozen allies are gearing up for the largest naval exercise ever in the Middle East focused on countering the threat of anti-ship mines. A wary Iran says it will be watching closely.

The maneuvers starting next week are the latest flexing of American military muscle in and around the Persian Gulf, even as Washington tries to convince ally Israel that diplomacy and sanctions aimed at pressuring Iran to scale back its nuclear program need more time to work.

U.S. Navy officials insist that the anti-mine exercise is not about any specific country or a response to Iranian threats to shut the narrow Strait of Hormuz at the mouth of the Gulf, the route for one-fifth of the world's oil.

But the drills will likely be perceived around the world as a challenge to Tehran, which has thousands of anti-ship mines it could deploy to disrupt shipping and drive up oil prices in response to any airstrike on its uranium enrichment facilities. The U.S. and several of its allies accuse Iran of seeking to develop nuclear weapons, but Iran says its atomic program is solely for peaceful purposes.

"This is one of many engagements conducted alongside regional defense forces," said Lt. Greg Raelson, a spokesman for the Navy's 5th Fleet. "Freedom of navigation through international waterways is critical to the international community and to nations in the region, including Iran."

The exercises, which will focus on a hypothetical extremist organization, are a way to boost cooperation with foreign navies and prepare to deal with threats that could block vital trade routes at sea, American officials say.

Raelson noted that waterborne bombs have struck a number of ships in the region in recent years, including a mysterious blast that damaged the Japanese oil tanker M. Star as it entered the Strait of Hormuz in 2010. An obscure al-Qaida-linked group later claimed responsibility for that attack.

Even so, the maneuvers carry an implicit message for Tehran.

"Who is the 800 pound gorilla in the room? It's Iran," said Scott Truver, a Washington-based naval analyst who has written about mine warfare. "I'm sure we're sending them a message of: Here's what we can do. So don't try it."

In 1988, an Iranian mine ripped open the hull of the guided missile frigate USS Samuel B. Roberts in the middle of the Gulf, injuring 10 crew members. The warship was part of a Navy force assigned to protect merchant vessels flying the U.S. flag. Washington responded days later with a one-day assault that destroyed two Iranian oil platforms and sank or crippled six Iranian vessels.

Next week's maneuvers are unprecedented in scope. France, Japan, Jordan and New Zealand are among the more than 30 countries expected to take part in the exercise, which begins Sunday and lasts through Sept. 27. Some, such as Britain, will be contributing ships and other hardware. Others are sending personnel and observers.

In addition to the Gulf, anti-mine practice is planned for the Gulf of Oman and the Gulf of Aden, the gateway to the Red Sea that has been a focus of international efforts to fight Somali pirates.

Practice exercises are vital in ensuring allied navies are able to work in tandem with their American counterparts, Truver said. Each country has its own command structures and routines, and problems arise in times of war if "you don't practice in peacetime," he noted.

Iran has said its forces will be monitoring the maneuvers.

"We are very sensitive about security in the highly strategic Persian Gulf and we are watching closely," Iranian Foreign Ministry spokesman Ramin Mehmanparast said when asked about the exercise. "They should pay attention that violations of security and tranquility in the region can be a very sensitive phenomenon."

Iran frequently conducts war games of its own, and is expected to launch another round sometime in the fall. The head of Iran's navy, Adm. Habibollah Sayyari, pledged earlier this month to put Iranian warships in international waters off the U.S. coast "in the next few years." Iran already has sent military vessels into the Mediterranean for the first time since the 1979 Islamic Revolution.

The comments are a sign of Tehran's growing alarm over a buildup of additional U.S. Navy ships and other reinforcements to the region.

Over the summer, the Pentagon deployed four more minesweepers to the Gulf along with the USS Ponce, an amphibious transport dock that was recently retrofitted to become what is known as an afloat forward staging base. That effectively means it is a mother ship that can act as a floating stop-off point for helicopters, patrol ships and special forces.

They join the four Avenger-class minesweepers the U.S. has long stationed in Bahrain, the tiny Gulf island nation that hosts the Mideast-focused 5th Fleet. Britain also stations minesweepers in the Gulf.

The aircraft carrier USS John C. Stennis recently deployed several months ahead of schedule as part of a Pentagon plan to ensure that two carrier strike groups are constantly in the region.


Associated Press writers Lolita C. Baldor in Washington and Nasser Karimi in Tehran, Iran, contributed to this report.