Country still negotiating for release of chartered vessel but prepared to use force.
An Iranian warship has entered the Gulf of Aden to protect Iranian vessels against pirates off the coast of Somalia, state radio said on Saturday.
"After travelling more than 4,000 nautical miles... an Iranian warship entered the Gulf of Aden to protect Iranian ships against pirates," the radio said, without further details.
Iran said last month it was negotiating with pirates who seized a ship it had chartered but that it was ready to use force to free the vessel.
The Hong-Kong-registered cargo ship Delight, with a 25-strong crew and 36,000 tonnes of wheat, was attacked in November in the Gulf of Aden as it headed for the Iranian port of Bandar Abbas.
In October, the authorities in Tehran paid a ransom to secure the release of an Iranian merchant ship hijacked off the Somali coast two months earlier.
Pirates have carried out more than 100 attacks in the key shipping lanes of the Gulf of Aden and the Indian Ocean since the start of this year.
Last month, they hijacked the Saudi super-tanker Sirius Star, carrying two million barrels of crude oil, and demanded a $25-million ransom for the boat and its crew.
It is one of about 17 ships, including an arms-laden Ukrainian cargo vessel, currently in pirate hands.
Numerous countries, including the United States, Belgium, France, Greece, Liberia and South Korea have all indicated a willingness to send or have already sent warships to the region and China has said it would also do so.
Countries in the region with help from US and EU countries must send these pirates to their demise and blow them up sky high, it's the only way to deal with these nomads, once the pirates are destroyed others will think twice before they make similar adventures, it's the only way to deal with thieves kill or be killed.