In its November issue, the magazine cites a US defence official as saying the United States was not yet sure what caused the problem, but suspected possible engine problems or difficulties with the missile's guidance system.

The test on September 21 was initially announced by Iranian defence minister Admiral Ali Shamkhani, who said it was a successful trial of a Shahab-D satellite launcher.

But Robert Walpole, US national intelligence officer for strategic and nuclear programmes, insisted the test was a failure, and that it involved a ballistic missile, according to JIR.

The magazine also quoted Walpole as saying the test was conducted near the city of Semnan, unlike the first two Shahab-3 test flights, which were carried out south of Tehran.

Walpole added that Iran had hundreds of short-range ballistic missiles, including a small number of Shahab-3s available for use in conflict, the magazine said.

Petagon officials said Iran has carried out only one successful flight test of the Shahab-3, the magazine reported. But that missile flew only 800 to 900 kilometres, not the 1,300 kilometres that Iran claims, the magazine added.