Iran's military fired at least two missiles at commercial ships transiting the Strait of Hormuz late Monday, according to a media report.
The US is likely to retaliate with strikes against Iranian targets following the attacks, said the Axios news site, citing two US officials.
The report came after the UK Maritime Trade Operations (UKMTO) center said a tanker was hit off the coast of Oman, triggering a fire aboard the vessel.
UKMTO said it received a report of an incident 8 nautical miles east of Limah.
"A tanker has reported being hit by an unknown projectile on the port side causing a fire, whilst travelling southbound," the agency said in a warning notice.
The agency said authorities were investigating the incident and advised vessels operating in the area to exercise caution and report any suspicious activity.
No casualties or environmental damage were reported, according to UKMTO.
