An Iranian mariner greets a U.S. Coast Guardsmen after being rescued. (U.S. Central Command)

A U.S. Coast Guard cutter, the Monomoy, picked up the Iranians off the coast of Oman about 3 a.m. Tuesday after their cargo dhow, the Ya-Hussayn, signalled with flares and flashlights that they were having engine trouble, Navy officials said.

It wasn’t the most dramatic operation in the annals of maritime history, but the rescue gave the U.S. military another public-relations victory in its ongoing feud with Iran over freedom of navigation in the region.

On Thursday, the Navy liberated 13 Iranian fishermen who had been hijacked and held hostage for several weeks by Somali pirates, also in the Arabian Gulf. In both cases, U.S. officials portrayed the Iranian sailors as extremely grateful for the emergency help — a sharp counterpoint to the Iranian government’s recent threat of war if U.S. forces don’t stay out of the nearby Persian Gulf.

“Without your help, we were dead,” Hakim Hamid-Awi, the owner of the Ya-Hussayn, was quoted as saying by a U.S. Fifth Fleet account of the rescue. “Thank you for all that you did for us.”

The Good Samaritan acts by U.S. forces also stood in contrast to the Iranian government’s harsh announcement Monday that it had sentenced an Iranian-American citizen to death, allegedly for spying.

The Coast Guard cutter was on patrol as part of a Navy maritime security task force that operates in the Middle East. The Americans found four of the Iranians floating on a life raft tied to their ship. All six were were provided with water, blankets and food. One was treated for a minor injury.

The sailors were later transferred to an Iranian Coast Guard vessel, U.S. officials said. No word on what happened to their broken-down dhow.

While some Iranian officials have grudgingly expressed gratitude for the rescues, Pentagon leaders remain concerned about the potential for a conflict with Iran over access to the Strait of Hormuz, the bottleneck in the Persian Gulf through which almost one-fifth of the world’s oil supply flows.

“If you ask me what keeps me awake at night, it’s the Strait of Hormuz and business going on in the Arabian Gulf,” Adm. Jonathan Greenert, the chief of naval operations, said Tuesday in Washington at a conference organized by the Center for a New American Security.