The largest daytime assembly of US warships in the Gulf since the 2003 Iraq War prepared yesterday to hold drills off Iran's coast in a major show of force that unnerved oil markets.

US Navy officials said Iran was not notified of plans to sail nine ships, including two aircraft carriers, through the Straits of Hormuz, a narrow channel in international waters off Iran's coast and a major artery for global oil shipments.

The maneuver raises pressure on the Islamic Republic, coinciding with a report by the UN atomic watchdog on Iran's nuclear program, which could lead to tougher sanctions.

Oil climbed toward US$70 as the US ships sailed into the straits, through which 40 percent of globally traded oil passes.

Rear Admiral Kevin Quinn, who is leading the group, said the ships would conduct exercises as part of a long-planned effort to reassure regional allies of US commitment to Gulf security.

"There's always the threat of any state or non-state actor that might decide to close one of the international straits, and the biggest one is the Straits of Hormuz," he told reporters on board the USS John C. Stennis aircraft carrier.

Tension with the US over Teheran's nuclear ambitions has raised regional fears of a military confrontation.

Highlighting the dangers of accidental escalation, a Navy official said the USS Stennis had received nine enquiries from nearby countries, two from Oman and seven from Iran, including one from an Iranian vessel that sailed close by.

Iran's Defense Minister Mostafa Mohammad Najjar said his country would resist any threat by its enemies.

Most US ships pass through the straits at night so as not to attract attention, and rarely move in such large numbers. 

Navy officials said the decision to send a second aircraft carrier was made at the last minute, without giving a reason.

The group of ships, carrying about 17,000 personnel and 140 aircraft scheduled to participate in the exercises that will take place over the next few weeks, crossed at roughly 03:55 GMT (11:55 AM Beijing time).

The maneuver comes less than two weeks after US Vice-President Dick Cheney, speaking aboard the Stennis during a tour of the Gulf, said Washington would stand with others to prevent Iran gaining nuclear weapons.

On a visit to Abu Dhabi a few days later, Iranian President Mahmoud Ahmadinejad threatened "severe" retaliation if the US attacked his country. He also urged Gulf countries to "get rid of" foreign forces, blaming them for insecurity in the region.

(China Daily May 24, 2007)