In a statement Mohammad Souri, chairman of the National Iranian Tanker Company, one of the world's largest, said world oil prices could rise if strategic sealanes went unprotected.
Iran, which has had two merchant ships hijacked by pirates in waters off Somalia, has previously said it could use force to protect its economic assets and has also called for a harder international military response.
The attacks on the fully-loaded supertankers, carrying two million barrels of crude oil each, the last of which occurred on the Haraz in November, varied between 50 minutes and four hours, Souri said, adding that the tankers narrowly avoided being boarded by speeding up. He gave no further details.
"Irrespective of the financial costs of the threat of piracy to property, the risk to seafarers' lives is clearly unacceptable," Souri said.
Souri called for armed security teams to be posted aboard merchant ships that passed through the Gulf of Aden for the length of the journey, a suggestion already being considered by the oil transporting industry.
Scores of attacks in the Gulf of Aden and Indian Ocean this year have caused big shipping firms to re-route their fleets, earned Somali pirates tens of millions of dollars in ransoms and prompted foreign navies to rush to protect merchant shipping.
A string of ships are still being held by gangs, among them a Saudi supertanker loaded with $100 million worth of crude oil. (Reporting by Stefano Ambrogi)
