July 29 (Reuters) - Iran's elite Revolutionary Guards fired ballistic missiles from underground for the first time as part of an annual military drill, Amirali Hajizadeh, the head of the aerospace division of the Guards, said in a video posted online by YJC, a news agency linked to Iran's state TV.
The video showed clouds of dust before the missiles streaked into the sky.
The military drill in the Gulf, which began on Tuesday, comes at a time of high tension between Tehran and Washington.
The U.S. military said the drill caused two bases with American troops in the region to go on heightened alert and said Tehran's missile launches were irresponsible.
There have been periodic confrontations in the Gulf in recent years between the Guards and the U.S. military, which has accused the Guards' navy of sending fast-attack boats to harass U.S. warships as they pass the Strait of Hormuz.
The video posted by YJC showed fast-attack boats firing missiles as well as missiles striking a mock-up U.S. aircraft carrier.
Tehran, which opposes the presence of U.S. and other Western navies in the Gulf, holds annual naval war games in phases in the strategic waterway, the conduit for some 30% of all crude and other oil liquids traded by sea. (Reporting By Babak Dehghanpisheh; Editing by Steve Orlofsky)
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