Another mysterious explosion in Iran this week, the third in a month, has stirred speculation that a mysterious hand was once again striking at Iran's nuclear programme.
The blast on Sunday occurred at a steel plant in the city of Yazd, killing seven people and seriously wounding 12 others. A number of the victims were foreigners, according to Iranian officials.
Citing Western intelligence sources, the German newspaper Die Welt reported last month that North Korea has been providing Iran and Syria with maraging steel - a type suitable, among other things, for use in gas centrifuges employed in uranium enrichment. Its strength and malleability also makes it useful in construction of exhaust systems for missile engines.
The United States and other countries monitor the import and export of maraging steel because of its possible use in centrifuges. Iran has not identified the type of steel being manufactured at the plant.
The blast was initially attributed by officials to water accidentally coming into contact with heated implements. Later, however, a local member of Parliament, Ali Akbar Oliaw, said the explosion had been touched off by defective ammunition that had been included in the scrap metal brought to the privately owned plant.
Ron Ben-Ishai, an Israeli military analyst, wrote yesterday in the newspaper Yediot Achronot that the explosion might have been a simple accident, but in view of the other recent explosions "it is hard to reject the possibility that this was intentional sabotage''.
Ben-Ishai noted that Sunday's blast had happened at a time not usually considered a work hour and that the mention of foreigners among the dead could have been a reference to North Korean experts who had come to train Iranians in processing the
Ben-Ishai suggested that sophisticated American unmanned aerial vehicles (UAVs), such as the one which fell into Iranian hands last week, might be closely tracking all aspects of the Iranian nuclear programme, including this.
A huge explosion at a missile testing base near Tehran on November 12 killed 17 people, including the general heading Iran's missile programme.
Iranian officials said the explosion was an accident, not sabotage.
On November 28 another explosion was reported at a factory in Isfahan which reportedly produces uranium gas which can be fed into centrifuges to produce the purified uranium needed to run a power plant, which Iran says is its only intention, or to make a nuclear bomb.
The Times reported it had seen satellite images that proved an explosion had occurred at the Isfahan site and quoted Israeli intelligence officials as saying the explosion was "no accident''.
The Washington-based Institute for Science and International Security, examining satellite images made a few days later, could find no signs of an explosion at the suspected nuclear facility but found that a site a few hundred metres away had recently undergone a "significant transformation'', including the levelling of several buildings.