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.
Local Pakistani sources also said the tankers had sent distress calls to the seaís littoral states, the report added.
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 Kokuka - 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.
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.
Meanwhile, 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 in the United Arab Emirates, where Abu Dhabi said a number of commercial vessels were targeted by "sabotage operations" last month.
(This item is being updated.)