U.S. Navy Fires on Ship in Persian Gulf, One Dead U.S. official says warning shots fired before small vessel was "engaged."

July 16, 2012  -- An American Navy ship fired on a boat in the Persian Gulf today, killing one person and injuring three others aboard the craft, U.S. naval officials told ABC News.

Lt. Greg Raelson, a spokesperson for the Navy's 5th Fleet, which is based in nearby Bahrain, said that a security team aboard the oil supply ship U.S.N.S. Rappahannock fired a .50 caliber machine gun at a "small motor vessel after it disregarded warnings and rapidly approached the U.S. ship" off the coast of Jebel Ali, a city approximately 30 miles from Dubai in the United Arab Emirates.

The Navy has launched a joint investigation with the UAE into the incident as details continue to emerge. A defense official described the offending vessel was a white pleasure craft, but two UAE officials told ABC News it was a fishing boat with four Indians and two Emiratis on board. The UAE's official news agency identified an Indian fisherman as the man who was killed.

There doesn't appear to be any indication the incident was terror-related, one of the UAE officials said.

A Navy official said it's not uncommon for Iranian speed craft to harass U.S. ships in the region, but in this case the boat wasn't Iranian.

"I can't emphasize enough that this has nothing to do with Iran," the official said.

Raelson said the small motor vessel that was hit by gunfire from the Rappahannock was "approaching at a high rate of speed" and "on a deliberate approach."

Another Navy official said it was "on a course that would have caused it to impact the Rappahanock... It wasn't just close, it was on a course that would have ultimately taken it to impact."

American sailors are trained to take special caution of any vessels that appear to be approaching their warships. In 2000 the destroyer U.S.S. Cole was attacked in the port of Aden, Yemen, by al Qaeda terrorists who used a small private craft armed with explosives to ram the ship, killing 17 American sailors.

Word of the shooting comes on the same day that the Pentagon confirmed that it had agreed to a recent request from U.S. Central Command to maintain a two carrier presence in the Middle East.

The carrier U.S.S. John C. Stennis has been ordered to head to the region four months ahead of schedule in September to replace the outgoing U.S.S. Enterprise. A Pentagon spokesman said the Stennis is being sent so that there is no gap in between two carrier assignments to the region.

On Sunday, the U.S.S. Eisenhower replaced the U.S.S. Abraham Lincoln in the region. By replacing the Enterprise, the U.S. will now be able to avoid having just one carrier in the region.

The U.S. Navy usually rotates one of its two carriers into the Persian Gulf while the other operates in the Arabian Sea providing air support for the war in Afghanistan.

ABC News' Brian Ross contributed to this report.

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