The crates of ammunition coming from an arms manufacturer in Ukraine were diverted to Syrian armed groups in the northern city of Aleppo, BBC reported on Monday.
Meanwhile, the BBC was not allowed to film the contents of the crates.
The Ukrainian firm Dastan specializes in naval weapons and missile complexes.
A recent New York Times report suggests that Saudi Arabia and Qatar have been funneling money and arms to Syrian insurgents for months.
Damascus accuses Saudi Arabia, Turkey and Qatar of backing a deadly insurgency that has claimed the lives of many Syrians, including security and army personnel.
Syria has been experiencing unrest since March 2011. Damascus says outlaws, saboteurs, and armed terrorists are the driving factor behind the unrest and deadly violence, but the opposition accuses the security forces of being behind the killings.
The Syrian government says that the chaos is being orchestrated from outside the country, and there are reports that a very large number of the insurgents are foreign nationals, mostly from Egypt, Algeria, Saudi Arabia, and Afghanistan.