Feb. 20 (Bloomberg) -- A U.S. aircraft carrier battle group led by the USS John C. Stennis arrived in the Persian Gulf region as part of a buildup of forces amid heightened tension with Iran.

The nuclear-powered Stennis, sent by President George W. Bush last month, arrived in the region Feb. 15 to join the USS Dwight D. Eisenhower as the second aircraft carrier battle group in the region, according to a statement from the U.S. Navy's Fifth Fleet, which operates in the Persian Gulf.

The deployment of additional naval forces ``is here to help foster stability and security in the region,'' Rear Admiral Kevin Quinn, commander of the naval force, said in the statement.

The U.S. and Iran are engaged in an increasingly tense standoff. The Bush administration contends Iran is taking steps to develop a nuclear weapon and meddling in Iraq. Last week, Bush said the Qods Force of Iran's Revolutionary Guard Corps is supplying explosives to militants in neighboring Iraq who are attacking U.S. troops.

The British Broadcasting Corp., citing unidentified diplomatic officials, reported today that the U.S. has contingency plans to attack Iranian nuclear sites and military infrastructure if the Islamic Republic is confirmed to be developing a nuclear weapon or is linked to a major strike against U.S. forces in Iraq.

Capability

``Certainly another carrier gives the U.S. the ability to act if they are provoked by Iran,'' Mustafa Alani, director of national security at the Dubai, United Arab Emirates-based Gulf Research Center, said in a telephone interview today.

Bryan Whitman, a spokesman for the U.S. Defense Department, called the BBC report ``ludicrous.'' He said that while the U.S. has ``significant concerns'' about both Iran's nuclear program and its activities in Iraq, American officials have said repeatedly that they intend to address those issues through diplomacy.

That message was reinforced at the White House, where Bush spokesman Tony Snow said that any speculation the U.S. is looking for a military confrontation with Iran is ``unwarranted.'' The administration has a ``clear commitment to pursue a diplomatic course'' with the Islamic Republic, he said.

Deadline

Iran faces a United Nations deadline tomorrow to suspend work on enriching uranium, which can be used to fuel a nuclear reactor or build a bomb. Iran's top nuclear negotiator, Ali Larijani, met today in Vienna with Mohamed ElBaradei, director general of the UN's nuclear agency. Larijani said they had ``good, constructive'' discussions.

Earlier, Iranian President Mahmoud Ahmadinejad dismissed the Security Council's demands.

The Iranian people ``will protect their nuclear rights until the end,'' Ahmadinejad, pronounced ah-ma-deen-ah-ZHAD, told supporters at a rally in Iran's northern Gilan province today that was carried live on state television.

Snow said that while the U.S. is willing to let the Iranians pursue civilian nuclear power, any steps that could lead to development of a weapon, including uranium enrichment, aren't acceptable.

``The United States and its allies on this are standing pretty firm, in terms of sending a clear message to the government in Tehran,'' Snow said. ``Iran should not be in a position to develop or possess nuclear weapons.''

The USS Stennis is accompanied in the Middle East by a flotilla of naval vessels including the guided-missile ships USS Antietam, USS O'Kane and USS Preble, according to the U.S. Navy statement.

Iran, the second-largest producer in the Organization of Petroleum Exporting Countries, dominates the Strait of Hormuz. The waterway links the Gulf with neighboring Omani waters and is the main thoroughfare for oil tankers shipping the region's crude exports.

To contact the reporter on this story: Andy Critchlow in Dubai at acritchlow1@bloomberg.net.

Last Updated: February 20, 2007 15:34 EST