Iran has tested an improved version of a medium-range missile capable of hitting Israel, bringing fresh calls for sanctions from Western leaders.

State television showed the launch of what it said was a Sejil-2 missile soaring out of the desert and said it hit its designated target.The test stoked tensions between Iran and the West, which is pressing Tehran to rein in its nuclear program.

Gordon Brown led the condemnation, saying: "This is a matter of serious concern to the international community and it does make the case for us moving further on sanctions."

A spokesman for the US National Security Council said: "At a time when the international community has offered Iran opportunities to begin to build trust and confidence, Iran's missile tests only undermine Iran's claims of peaceful intentions.

"Such actions will increase the seriousness and resolve of the international community to hold Iran accountable for its continued defiance of its international obligations on its nuclear program."

The missile test followed a series of launches and the Iranian defence minister said it was intended to improve the speed of the Sejil-2, the longest-range weapon in its arsenal at an estimated 1,250 miles.

"It is impossible to destroy the missile with anti-missile systems because of its radar-evading ability," the minister, General Ahmad Vahidi.

The weapon could be used to retaliate against Israel should it decide to strike against the Iranian nuclear programme, which the country regards as an "existential threat".

It could also be used to carry a nuclear weapon, if the Iranians succeed in mastering the technology to turn a nuclear device into a warhead.

The test came shortly after the United States House of Representatives passed legislation that would impose sanctions on companies supplying refined fuel to the country.

Tags: Sejil-2, Country, United States, Iran, Gordon Brown, Missile Test.