TEHRAN - Iran's foreign ministry spokesman said Saturday that the US rescue of 13 Iranian sailors from captivity by Somali pirates is a "humanitarian" action.

The campaign against pirates is an international obligation, and Iran has conducted such operations in the past in line with the international campaign against pirates to release sailors of other nations, the official IRNA news agency quoted Ramin Mehmanparast as saying.

The US Navy said on Friday that it has rescued 13 Iranian hostages held by Somali pirates in the Arabian Sea, days after tension escalated as Iran warned against the return of a US aircraft carrier strike group to the Persian Gulf.

The US guided-missile destroyer USS Kidd, part of the USS John C. Stennis aircraft carrier strike group which just departed the Gulf days ago, responded to a distress call from the Iranian boat Al Molai, held by Somali pirates for more than 40 days, the US Navy said in a statement.

A US Navy team from the USS Kidd was taken by a helicopter to board the Iranian boat, used as a "mother ship" by the pirates, and detained 15 pirates.

The Iranians were freed and headed home after the US Navy team gave them food, water and medical care.

The rescue operation came amid rising tension between the US and Iran, whose military chief on Tuesday warned Washington against sending the aircraft carrier back to the Gulf. The USS John C. Stennis was sent to the Gulf to observe the 10-day Iranian naval exercises dubbed "Velayat 90" that started on December 24.

The US rejected the Iranian warning, saying it will continue to deploy its aircraft carriers to the Gulf to protect freedom of navigation.

Iran, facing increased sanctions by the US and its allies over its nuclear program, threatened during the "Velayat 90" exercise that it will seal off the Strait of Hormuz, one of the most critical global oil routes, if its oil exports are sanctioned. In response, the Pentagon warned that "interference with the transit or passage of vessels through the Strait of Hormuz will not be tolerated."

Deputy Commander of Iran's IRGC Brigadier General Hossein Salami last week dismissed the US warnings over Iranian threats to close the Strait of Hormuz, adding Tehran does not seek Washington's permission to implement its defense strategies in the Persian Gulf.

Iran's foreign ministry spokesman Ramin Mehmanparast said Wednesday the Persian Gulf region is highly important for global energy supply, and that Iran is not after creating tension.

"But if the atmosphere changes into a war spirit and the situation in the region changes, all the decisions (of Iranians) would be made on the basis of new condition," Ramin Mehmanparast told Xinhua.