A massive blast at Iran’s largest port which killed more than 100 and maimed 1,000 more was a cargo of rocket fuel for ballistic missiles exploding, it was claimed today. The fuel is reported to have been shipped from China and according to Iranian news agency ISNA was never declared at customs.

And today, it's been claimed a massive cover-up was underway by the Iranian regime keen to play down both the body count and the source of the catastrophic blast at Iran’s biggest port Shahid Rajaei, in the city of Bandar Abbas. The official line is that there are 40 dead and the source of the explosion is unknown. But sources on the ground in Iran say at least 100 were killed as the containers of sodium perchlorate, which is used for solid fuel in ballistic missiles, went up.

Experts say the amount of sodium perchlorate could have fuelled hundreds of Iran’s medium range Khybar-Shikan and Fattah missiles, or the shorter range Fateh-110 and Zolfaghar missiles.

The Islamic regime, headed by Ayatollah Ali Khamenei is known to be pushing ahead with its nuclear programme and is desperate to achieve a nuclear ballistic missile, despite ongoing talks with the US to abandon its atomic ambitions.

Maryam Rajavi, head of the National Council of Resistance of Iran, whose sources from inside the country are making claims about a cover-up, said: “Explosions continue to rock Bandar Abbas as more containers detonate.

“The true death toll is several times higher than officially reported and certainly exceeds 100.

“The IRGC, intelligence forces, and other organs of repression have mobilised, not to contain the fires or rescue the wounded, but to control the situation and cover up the shipment of solid fuel for ballistic missiles and the full scale of the disaster.”

The blast at the port took place almost exactly as US and Iranian delegates would have been sitting down to a third weekend of tentative talks to de-nuclearise Iran, sparking theories the explosion was no accident.

Iran has denied the presence of sodium perchlorate. Islam Revolutionary Guards Brig Gen Reza Talaei-Nik, who serves as Deputy Defence Minister, said: “There were no imported or exported shipments related to military use or rocket fuel at the site of the incident.”

While an editorial in Tehran’s Persian language daily newspaper Ham-Mihan claimed: “It is improbable that the explosion’s concurrence with the start of technical talks between Iran and America is coincidental” and suggested Israel was behind the blast.

But in February it was widely reported that a ship called the Golbon docked in Iran from China carrying 1,000 tons of ammonium perchlorate, another substance commonly used to make solid rocket fuel.