US drone attacked by Iran in international waters: Pentagon

A surveillance American drone in the Arabian Gulf was intercepted and attacked by Iranian jets earlier in November, the Pentagon has said.

"I can confirm that on November 1, at approximately 4.50 am Eastern Daylight Time, an unarmed, unmanned MQ-1 US military aircraft conducting routine surveillance over the Arabian Gulf was intercepted by Iranian Su-25 Frogfoot aircraft and was fired upon with guns," said Pentagon press secretary George Little.

"The incident occurred over international waters approximately 16 nautical miles off the Iranian coastline. The MQ-1 was not hit and returned to its base safely. We have briefed relevant members of Congress on the incident," he said, adding that Defence Secretary Leon Panetta and US President Barack Obama were informed about it.

The United States has communicated to the Iranian administration that it will continue to conduct surveillance flights over international waters over the Arabian Gulf, consistent with its long-standing practice and its commitment to the security of the region, Little said.

"We have a wide range of options from diplomatic to military to protect our military assets and our forces in the region and we will do so when necessary," he said.

According to the Pentagon spokesman, the American unmanned and unarmed aircraft had not breached Iranian airspace.

"It was always flying in international airspace. The internationally recognised territorial limit is 12 nautical miles off the coast. And we never entered the 12 nautical-mile limit," he said.

The drone was not hit and did not receive any damage, Little said, adding that it was fired at twice by the Russian made Iranian jets.

"Our working assumption is that they fired multiple rounds to take it down. You will have to ask the Iranians why they engaged in this action," he said.

"The aircraft, once it came under fire at approximately the 16 nautical-mile range, moved further out. And the Iranian aircraft continued to pursue the MQ-1 for some period of time before letting it return to base," he added.

Little claimed that no other aircraft were deployed to respond to the Iranian action.

Asserting that the US will continue to fly drones in the international water, Little said there is absolutely no precedence for this.

"This is the first time that a UAV has been fired upon, to our knowledge, by an Iranian aircraft," he said.