They are set to be the future of stealth transport for soldiers - and can run on electricity and everything from petrol to olive oil.

The Defense Advanced Research Projects Agency, or DARPA, has shown off the two projects is had backed to create next generation stealth motorbikes.

The Silent Hawk by Logos and the Nightmare from LSA Autonomy are both being funded by the agency.

The Logos Silent Hawk. The hybrid engine bike would use diesel, gasoline or jet fuel for normal operations. But when it gets closer to the enemy, it would run almost silently on electricity.

The two prototypes have been shown at the National Defense Industrial Association's Special Operations Forces Industry Conference in Tampa.

Both bikes feature cutting-edge hybrid multi-fuel engines that can burn a variety of combustibles from jet fuel to olive oil.

'If it's gasoline, tell it it's gasoline, tell it it's something else. It will figure it out,' Alex Dzwill, and engineer with Logos, told Defence One.

When asked if you can run it on other fuels, such as olive oil, he said ' “Theoretically, yeah,” said Dzwill.

The bikes have two modes, a traditional 'loud mode', and a quiet mode that switches the bike to operating from a battery.

The loud mode is akin to a garbage disposal at around 80 decibels, while quiet mode is 55 decibels, about as loud as an indoor conversation.

The idea is that for normal operations, the bike would use diesel, gasoline or jet fuel. But when it gets closer to the enemy, it would run almost silently on electricity.