U.S. Navy Exercise Near Iran No Coincidence, Official Says

The U.S. Navy is offering a huge show of military might near the location where Iran seized 15 British sailors and marines five days ago, in what is seen as a clear effort to send a message to Iran, a senior military official told ABC News' Martha Raddatz in Bahrain.

Twelve ships, 100 aircraft and 12,000 sailors are taking part in the war games designed to get the attention of Iran.

The naval exercise went on all day today and will continue Wednesday, with F-18 fighter jets roaring from the deck of both aircraft carriers in the first appearance of two U.S. carriers in the Gulf simultaneously since 2003.

U.S. naval officials in Bahrain told ABC News that the operation was hastily planned after the 15 Britons were seized Friday, yet the Bush administration would not say publicly that this is the case.

Diplomacy, Options Considered

Friday, when the sailors were first captured, there was every expectation that the men would be released within a few days, which is what happened during a similar incident in 2004.

British Prime Minister Tony Blair said today that unless the sailors and marines were returned safely, the crisis could escalate.

"I hope we manage to get them to realize they have to release them," Blair said. "If not, then this will move into a different phase."

The U.S. military exercise today goes well beyond the seizure of the Britons to address the overall tensions with Iran to include the transfer of Iranian weapons into Iraq and the standoff over Iran's nuclear program.

"The Navy is a very useful tool for deterring enemies," said Loren Thompson of the Lexington Institute. "It's a lot of power, and it can deploy just about anywhere that has a coastline."

For now, Iran is holding firm and has threatened to charge the captured sailors with illegally entering what they claim are Iranian waters -- waters that the U.S. carriers will continue to monitor from very close by.

Watch "World News" Wednesday for Martha Raddatz's continuing reports from the Middle East.