Washington, Nov 9 (IANS): Iranian fighter jet had attacked a US drone but missed it, the US Defense Department has confirmed.

In an announcement, Pentagon press secretary George Little said the Iranian aircraft fired at the US drone and followed it as it flew over the Arabian Gulf last week, Xinhua reported Friday.

"I can confirm that on November 1, at approximately 4.50 a.m. Eastern Daylight Time, an unarmed, unmanned MQ-1 US military aircraft conducting routine surveillance over the Arabian Gulf, was intercepted by an Iranian SU-25 Frog-foot aircraft and was fired upon with guns," he said.

Little said the incident occurred over international waters, approximately 16 nautical miles (about 30 km) off of the Iranian coastline, emphasising "the MQ-1 was not hit, and returned to its base safely."

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

"We believe they fired at least twice and made at least two passes," Little said, confirming both Congress and the White House were notified of the incident, and the US responded to Iran through the "Swiss protective powers".

"The United States has communicated to the Iranians that we will continue to conduct surveillance flights over international waters, over the Arabian Gulf, consistent with longstanding practices and our commitment to the security of the region," Little said.

While insisting the aircraft was "never in Iranian airspace. It was always flying in international airspace," Little said the US side can respond using a "wide range of options -- from diplomatic to military -- to protect its military assets and forces in the region, and "will do so when necessary" .