Dozens of Iranian engineers and 15 Syrian soldiers were killed in an explosion while conducting a top-secret experiment – providing new evidence that the two countries are working together to develop weapons of mass destruction, it was reported yesterday.

The blast occurred while the joint Syrian-Iranian team was trying to mount a chemical warhead on a Scud missile, spreading lethal agents – including deadly Sarin and mustard gas – into the air.

The July 23 accident occurred at a factory in northern Syria, 50 miles from the Turkish border, created for the purpose of adapting ballistic missiles to carry chemical weapons, Jane’s Magazine reported.

A fire that started in the missile’s engine led to an explosion near a storage facility for chemical substances, the British-based magazine reported on its Web site.

This summer’s accident confirms that Iran, which has been trying to develop its own nuclear weapons, is working with its Mideast ally to secure warheads capable of inflicting widespread destruction.

Iranian President Mahmoud Ahmadinejad has come under fire from the United States and other nations for going ahead with his country’s nuclear-energy program.

The incident was reported at the time by Syria’s official news agency.

But the report included only information on the Syrian casualties and did not mention Iranian casualties.

The Syrian report claimed the explosion was caused by a “heat wave,” although the blast took place at around 4:30 a.m.

The Syrian government rejected the possibility of sabotage.

Syria has a long history of developing chemical weapons.

Since 1985 it has manufactured a variety of missiles capable of carrying Sarin. Russian intelligence has claimed that Syria has a stockpile of hundreds of chemical aerial bombs.

According to Jane’s, the facility where the accident took place was built as part of a cooperation agreement signed between Syria and Iran in 2005. With Post Wire Services

clemente.lisi@nypost.com