A U.S. high-altitude drone was shot down Thursday by an Iranian surface-to-air missile over the Strait of Hormuz amid heightened tensions in the region after last week’s attacks on two oil tankers, a source told Fox News.

A commander for Iran’s Revolutionary Guard said the shooting sends `a clear message’ to the U.S. He said while Iran has no intention of war with anyone, it’s “ready for war.”

The U.S. Navy’s MQ-4C drone, , which has the same wingspan as a Boeing 737, was over international airspace at the time and about 17 miles from Iran, the source said.

Capt. Bill Urban, a U.S. Central Command spokesman, declined to comment on the reported attack when reached by the AP, but he said no drone was over Iranian territory.