Iran successfully test fired a medium-range surface-to-air missile on Sunday during navy war games taking place near the strategic Strait of Hormuz, a spokesman for the manoeuvres said, according to the official IRNA news agency.

"This medium-range surface-to-air missile is equipped with the latest technology to combat radar-evading targets and intelligent systems which try to disrupt missile navigation," Commodore Mahmoud Mousavi was quoted as saying.

He said it was the first time Iran had tested the missile, which was "domestically designed and built."

Mousavi also told the ISNA news agency that the 10 days of war games were to end Monday with all ships and submarines exercising a new tactic to practise the closure of the strait "if Iran's navy so chooses."

It was not immediately known whether the missile was fired from a ship or from land. Other details about the missile, including the distance it can fly, were not given.

The missile's launch and the war games are meant to show Iran's military capabilities at a time that the United States and other Western nations are increasing pressure over Tehran's nuclear programme.

The fact that they are taking place near the Strait of Hormuz has focused attention on Iran's threats in recent days that it could close the narrow channel at the entrance to the Gulf if more sanctions are imposed.

In a move that could intensify a brewing Gulf showdown, US President Barack Obama on Saturday signed into law tough new sanctions targeting Iran's central bank and financial sector.

Twenty percent of the world's oil passes through the Strait of Hormuz, making it the "most important chokepoint" globally, according to the US Energy Information Administration.

Iran's navy was to test a number of missiles Sunday, targeting aerial drones, Mousavi told state television. It was also to launch torpedoes from submarines.

The exercises were taking place in waters to the east of the Strait of Hormuz, in the Gulf of Oman and the Gulf of Aden.

Iran said the scale of the manoeuvres were unprecedented in terms of the number of navy units taking part and the area involved: 2,000 square kilometres (770 square miles).