Iran has sent six warships to international waters, including the Gulf of Aden, to show its ability to confront any foreign threats, its naval commander said on Monday.

Admiral Habibollah Sayyari, quoted by the ISNA news agency, made the announcement five days after Iran said it test-fired a surface-to-surface missile with a range of 2,000 km, putting Israel and US bases in the area within reach.

Iran said on May 14 it had sent two warships to the Gulf of Aden to protect oil tankers from the world's fifth-largest crude exporter against attacks by pirates but ISNA did not make clear whether they were among the six Sayyari talked about.

Iranian waters stretch along the Gulf, the Strait of Hormuz and the Sea of Oman. Iran has threatened to block the Strait of Hormuz, through which about 40 per cent of the world's traded oil is shipped, if it were attacked over its nuclear programme.

'Iran has dispatched six warships to international waters and the Gulf of Aden region in an historically unprecedented move by the Iranian Navy,' Sayyari told a gathering of armed forces officials, IRNA reported.

Sayyari said that preserving Iran's territorial integrity in its southern waters called for the 'perseverance and firmness' of the navy.

The move to dispatch the warships 'is indicative of the country's high military capability in confronting any foreign threat on the country's shores,' Sayyari said.

The ISNA report did not mention the threat of pirate attacks, which, fuelled by large ransoms, have continued almost unabated despite the presence of an armada of foreign warships patrolling the Indian Ocean and Gulf of Aden.

In January, pirates released an Iranian-chartered cargo ship carrying 36,000 tonnes of wheat to Iran from Germany that was seized in November. In March, a regional maritime official said Somali villagers had detained another Iranian vessel.-Reuters