4/2/2007 5:50:00 PM GMT

"Two US aircraft trespassed into Iranian airspace northwest of (the southwestern port city of) Abadan before flying southwest into Iraq," said Colonel Aqili, commander of the Islamic Revolution Guards Corps (IRGC) in Abadan.

"The planes left white vapour trails, attracting the local people's attention," he said.

The incident took place near Iran's border with Iraq, where the U.S. and British military bases are located.

The types of the two U.S. airplanes hadn’t been identified.

Meanwhile, the U.S. Navy said that nuclear-powered aircraft carrier USS Nimitz will be deployed in the Persian Gulf by the end of this month-- a move that comes amid growing tensions between the West and Iran over its arrest of 15 British navy personnel.

A Navy official said the new strike group will sail from San Diego for the Gulf on Monday to replace the carrier Dwight D. Eisenhower, which this week took part in war games exercises in the Gulf with another carrier, John C. Stennis.

Nimitz will be in position by late April, but there will be no overlap with the Eisenhower, and the number of U.S. carriers in the area would stay at two, Lt. Cmdr. Jeff Davis said. 

Spokesmen for the 5th fleet, based in Bahrain, have said the exercises were meant to reassure allies of the U.S. commitment to security in the region. 

Earlier, U.S. Navy officials claimed that the war games weren’t organized in response to the arrest of the British sailors, nor were they aimed at threatening Tehran, whose navy operates in the same waters.

Russian Foreign Minister Sergei Lavrov has warned Washington not to aggravate tensions with Tehran with its naval presence in the Gulf.

Last week, Iranian state media quoted Ali-Reza Tangsiri, a Revolutionary Guards navy commander, as saying that Tehran, which last Thursday also launched a week of naval exercises in the Gulf, was monitoring foreign warships closely.

Tangrisi also played down the U.S. naval war games. "Based on our forces' observations, (U.S.) claims ... about a big American maneuver in this region are not true," he said.

Last February, the Iranians said they tested missiles that could "sink big warships" in the Gulf.

On March 23, Iran arrested eight Royal Navy sailors and seven Royal Marines who Tehran said had illegally entered Iranian territorial waters near the Gulf. 

Britain insists that the Britons were operating in Iraqi waters under a UN mandate.

On Monday, Iranian state TV showed footage of the British navy personnel, saying that they all gave detailed confessions of their entry into Iranian waters.

"All evidence, including the GPS carried by the British military and also the frank confessions of all 15 British personnel shows that they have entered Iran's territorial waters without permission," state television said.

Yesterday, Iran's official Arabic language TV channel aired short video clips showing two of the 15 Britons pointing to a map of the Persian Gulf.

Al-Alam satellite TV said the two men "confessed" to "illegally" trespassing in Iranian waters.

Pointing to a map, one of the men, Captain Chris Air said: "At about 10 o'clock in the morning, we were seized, apparently at this point here, from their maps, from the GPS they've shown us, which is inside Iranian territorial waters."

"So far we have been treated very well by the people here. They have looked after us and given us enough food," he added.

Britain's Foreign Office denounced the video, saying it was "completely unacceptable for these pictures to be shown on TV."

Britain, which unlike the U.S. has diplomatic ties with Tehran and has an embassy there, says that it is continuing bilateral contacts with Iranian officials to resolve the standoff.

However, these talks have borne little fruit and Iranian pledges last week that it would release the sole woman detained, Faye Turney, came to nothing after Tehran complained about Britain's behavior.