Media reports say two large oil tankers have been hit by explosions in the Sea of Oman.
Iranís Al-Alam television network cited local sources in Oman as saying that two successive explosions were heard in the Sea of Oman - also called the Gulf of Oman - on Thursday morning.
The sources said the blasts were caused by attacks on the tankers, according to the report.
The tankers had sent distress calls to the seaís littoral states.
The area is near the Strait of Hormuz, a strategic waterway through which nearly one-third of all oil traded by sea passes.
Reuters, citing four shipping and trade sources, said two tankers - identified as the Marshal Islands-flagged Front Altair and the Panama-flagged Japanese-owned Kokuka Courageous - had been hit in suspected attacks in the Gulf of Oman, and that the crew had been evacuate from the vessels.
The crew were safe, the sources added.
Iranian rescue workers have rushed to the assistance of two oil tankers hit by yet unspecified accidents in the Sea of Oman, transferring all of their 44 crew members to its southern shores, IRNA reported.
The Marshall Islands-flagged tanker was, according to reports, heading from Qatar to Taiwan when a fire broke out on the tanker approximately 25 miles from Iranís Jask port city.
The Panama-flagged ship was also en route from a port in Saudi Arabia towards Singapore when a fire broke out approximately 28 miles from Jask.
The US Navyís Bahrain-based Fifth Fleet told Reuters that its naval forces are assisting tankers in the Gulf of Oman after receiving two distress calls.
"We are aware of the reported attack on tankers in the Gulf of Oman. US Naval Forces in the region received two separate distress calls at 6:12 a.m. local time and a second one at 7:00 a.m.," Joshua Frey of the Fifth Fleet said.
The Kokuka Courageous tanker was damaged in the incident, a spokesman for the vesselís manager BSM Ship Management (Singapore) said.
"The Kokuka Courageous remains in the area and is not in any danger of sinking. The cargo of methanol is intact," the spokesman said.
The vessel is about 14 nautical miles off Iran and about 70 nautical miles from Fujairah in the United Arab Emirates (UAE), where a number of commercial vessels were targeted by sabotage operations last month.
The Norwegian shipping firm Frontline also confirmed that its oil tanker Front Altair was on fire after an incident in the Gulf of Oman, Norwegian newspaper VG reported, quoting a company spokesman.
All 23 crew members were brought to safety at a nearby vessel, the spokesman added.
The al-Mayadeen satellite TV reported that Frontlineís tanker sank into the sea.
Earlier, the Associated Press reported that the United Kingdom Maritime Trade Operations - which is run by the British navy - warned that an unspecified incident has taken place in the sea and was urging "extreme caution."
In another report, shipping newspaper Tradewinds claimed, citing unnamed industry sources, that an oil tanker owned by Norwayís Frontline had been struck by a torpedo off the coast of Fujairah.
(This item is being updated.)