TEGUCIGALPA, Honduras — The Honduran Air Force pilot did not know what to do. It was the dead of night, and he was chasing a small, suspected drug plane at a dangerously low altitude, just a few hundred feet above the Caribbean. He fired warning shots, but instead of landing, the plane flew lower and closer to the sea.

“So the pilot made a decision, thinking it was the best thing to do,” said Arturo Corrales, Honduras’s foreign minister, one of several officials to give the first detailed account of the episode. “He shot down the plane.”

Four days later, on July 31, it happened again. Another flight departed from a small town on the Venezuelan coast, and using American radar intelligence, a Honduran fighter pilot shot it down over the water.

How many people were killed? Were drugs aboard, or innocent civilians? Officials here and in Washington say they do not know. The planes were never found. But the two episodes — clear violations of international law and established protocols — have ignited outrage in the United States, bringing one of its most ambitious international offensives against drug traffickers to a sudden halt just months after it started.