The world's biggest truck-maker has unveiled two new battery-powered models, as it looks to protect its market dominance.

Daimler, the German firm best known for its Mercedes brand, said Wednesday that it wanted to have an all-electric big rig called Freightliner eCascadia ready for commercial sale by 2021. A smaller medium-duty Freightliner eM2 106 is also planned by the same date.

The trucks were revealed Wednesday at Daimler's North American headquarters in Portland, Oregon.

The eCascadia is designed to travel on major highways with a range of about 250 miles between charges. The eM2 has a range almost as long, at around 230 miles, but is designed for local delivery and final mile use.

Daimler said in a statement that a fleet of 30 vehicles would be delivered to customers later this year for testing.

The German company's leading position in the truck market has been put under pressure by Elon Musk's all-electric battery-powered Tesla Semi, revealed in November. That vehicle is set to have a range of 500 miles and is scheduled to hit the market in 2019.