The indispensable Laura Rozen quotes Intelligence Online, which says the targets were Korean SCUD missile parts:
In attacking Dair el Zor in Syria on Sept. 6, the Israeli air force wasn’t targeting a nuclear site but rather one of the main arms depots in the country.
source link Dair el Zor houses a huge underground base where the Syrian army stores the long and medium-range missiles it mostly buys from Iran and North Korea. The attack by the Israeli air force coincided with the arrival of a stock of parts for Syria’s 200 Scud B and 60 Scud C weapons.
The parts were shipped from North Korea aboard a container ship flying the Panamanian flag. The U.S. Navy wanted to board the ship in Morocco’s territorial waters but Rabat vetoed the operation. The parts were loaded aboard six trucks in the Syrian port of Tartus on Sept. 3 and took three days to reach Dair el Zor. The trucks and their loads were destroyed the moment they arrived at the underground base. A unit of military police that escorted the convoy was also wiped out in the attack.
The source site really interesting part is below the fold: