Eight engines for F-16 fighter jets were stolen from an Israeli military base.

The engines were reported stolen on Nov. 6 from an unspecified Air Force Base. It's unknown who is responsible but authorities suspect that it may have been an inside job, according to JTA.

Officials for the Israel Defense Force said an investigation has been launched to find out who is responsible and how the 1.5 million ton engines were moved.  

There was no sign of forced entry and with the extreme weight of the eight engines, investigators are focusing on the lead that there was internal help in the disappearance.

The American-built engines were taken out of their respective aircraft to receive repairs at the time of their removal. However, they still have a high value on the black market and officials think the motive for the theft was likely to sell them as whole or for scrap.

There is also the possibility that they were taken by enemies of Israel to study the technology behind the engines' construction.

"They're still more modern than anything in the Iranian air force inventory, and they would even be helpful to China in their jet engine development," said Richard Aboulafia, vice president for analysis with the Teal Group, according to Defense Tech.

This is the latest act of thievery from an Israeli military base since equipment and ammunition was stolen from the Tze'elim military facility in July 2012 by a group of bandits in SUVs.

In a separate incident that took place June 2011, eight jet engines were stolen near Jerusalem. The engines were for F-15 and F-16 fighter jets and taken at the Tel Nof military base. The incident was downplayed as officials said the engines were too old to use properly and were likely sold for scrap.