An explosion has damaged an Iranian cargo ship anchored off Yemen's Red Sea coast that is allegedly used by the Revolutionary Guards for spying, Iran's foreign ministry has confirmed.
The blast that targeted the Saviz on Tuesday caused no casualties and was under investigation, reports the BBC citing a ministry spokesman.
"The vessel was a civilian ship stationed there to secure the region against pirates," he added.
The New York Times reported that Israel had told the US it attacked the Saviz.
Israeli officials did not comment, but it is the latest in a series of attacks on Israeli- and Iranian-owned ships, for which the arch-foes blame each other.
Iranian foreign ministry spokesman Saeed Khatibzadeh said the explosion that hit the Saviz at about 06:00 local time (03:00 GMT) on Tuesday caused only "minor damage".
"Technical investigations about the incident and its cause are going on, and our country will take all necessary measures about it through international organisations," he added.
Khatibzadeh said the Saviz was a "non-military ship", which was helping to "provide security along shipping lines and combat pirates".
"The ship was practically operating as Iran's logistical station... in the Red Sea, thus the ship's information and mission had been already announced to [the International Maritime Organization] officially."
Iran's semi-official Tasnim news agency cited unnamed sources as saying the explosion was caused by "limpet mines attached to the hull of the ship".