Iran has insisted that an explosion that killed the architect of its missile programme was not carried out by Israel or the US, despite widespread reports that it was the work of the Israeli secret service, the Mossad.

On Saturday a huge blast at the Alghadir missile base at Bid Ganeh, 30 miles to the west of Tehran, killed 17 of the country's elite revolutionary guards, including Major General Hassan Tehrani Moghaddam, a senior commander described as the pioneer of the regime's missile programme.

A senior Iranian military official on Wednesday denied reports that Israel was linked to the blast. Speaking at a ceremony commemorating those killed on Saturday, Iran's armed forces joint chief of staff, Major General Hassan Firouzabadi, said in quotes carried by the semi-official Fars news agency: "The recent incident and blast is not related to Israel or America."

Firouzabadi said that the explosion has disrupted the production of "a very important product" but the base would resume working soon, without elaborating on the nature of what the base had been making.

It is believed that the Alghadir base is a depot for Iran's Shahab-3 missiles, which have a range of 1,200 miles, making them capable of reaching Israel.

After the incident Iran was quick to state publicly that an accident caused the explosion, saying that it happened while ammunitions were being moved. But anonymous sources with close ties to Tel Aviv and Tehran have since spoken to the press alleging that the Mossad was behind it.

Iran regularly points the finger at Israel and the US as the source of internal disputes but this time Tehran leaders are adamant that their enemies are innocent.

In recent years Iran's nuclear programme has experienced a series of dramatic setbacks by the assassination of its scientists and a computer worm believed to have been designed to sabotage the country's enrichment of uranium.

These incidents, seen as part of a covert war against Iran led by Israel, aimed at halting its nuclear activities, have given weight to speculation that Saturday's blast could also be part of a shadow war over Iran's nuclear programme, but this time with the aim of halting the regime's missile progress.

Many analysts believe that Israel and its allies have opted for a covert war instead of a costly military strike, which is believed to be difficult to achieve.

Time magazine reported on Sunday that the Mossad carried out the blast through sabotage, citing western intelligence sources. An Iranian source with close ties to the clerical establishment told the Guardian that Israel was responsible.

If an Israeli link to the blast turns out to be true, the Iranian government would be hugely embarrassed by the extent of the enemy's access to its most sensitive activities.

Several Iranian officials have therefore stepped forward, echoing Firouzabadi's comments and ruling out the possibility of the involvement of a foreign hand, even before an internal investigation has properly begun.