A/P TEHRAN — An official said on Monday that Iran has summoned a Swiss envoy over what seems to be a U.S. seizure of Iranian crude oil from a ship that had been stranded in Houston for months off the coast of Texas.

The comments made by Nasser Kanaani, a spokesman for the Iranian Foreign Ministry, represent the most recent development in the story of the oil that formerly resided on the ship Suez Rajan, which had become entangled in the broader hostilities between the United States and the Islamic Republic. At the same time, Tehran and Washington are negotiating the release of five Iranian-Americans in exchange for billions of dollars in frozen Iranian assets in South Korea.