WASHINGTON — Just days after Iranian leaders warned the U.S. to keeps its aircraft carriers out of the Persian Gulf, a U.S. Navy ship that had just finished operations in the Gulf rescued an Iranian fishing boat that had been commandeered by suspected Somali pirates.

U.S. Navy officials said that American forces flying off the guided-missile destroyer USS Kidd responded to a distress call from the Iranian ship, the Al Molai, which had been held captive by pirates for more than 40 days.

A U.S. Navy team boarded the ship Thursday and detained 15 pirates who had been holding the 13-member Iranian crew hostage and were using the vessel as a “mother ship” for pirating operations in the Persian Gulf.

The rescue came amid escalating threats from Tehran, including assertions by Iran’s Army chief that American vessels are not welcome in the Gulf. And Iran has also warned that it could block the Strait of Hormuz, the strategic waterway that carries to market much of the oil pumped in the Middle East.

The Iranian threats, which were brushed aside by the Obama administration, were in response to strong economic sanctions against Iran over its disputed nuclear enrichment program. Last week, President Barack Obama signed into law new sanctions targeting Iran’s Central Bank and its ability to sell petroleum abroad.

According to the Navy, the USS Kidd was part of the USS John C. Stennis Carrier Strike Group, which had recently gone through the Strait into the northern Arabian Sea.

A Navy search and seizure team was taken by helicopter from the USS Kidd to the Al Molai and met no resistance from the pirates, who surrendered quickly.

“The Al Molai had been taken over by pirates for roughly the last 40-45 days,” said Josh Schminky, a Navy Criminal Investigative Service agent aboard the Kidd. “They were held hostage, with limited rations, and we believe were forced against their will to assist the pirates with other piracy operations.”

Schminky said the Iranian crew members said they were given limited rations and that they were apparently forced against their will to assist the pirates. The U.S. team gave the crew food, water and medical care, and transferred the captured pirates to the USS Stennis, where they still remain.

“The Captain of the Al Molai expressed his sincere gratitude that we came to assist them. He was afraid that without our help, they could have been there for months,” said Schminky in a prepared release.