(Reuters) - Amazon ( AMZN ) said on Tuesday it has ordered 200 Mercedes-Benz fully-electric eActros 600 heavy goods vehicles from Daimler to serve the German and UK markets in its largest electric truck order so far.

The e-commerce giant said the trucks will start joining its network later this year and will be deployed on "high-mileage routes" across Amazon's ( AMZN ) middle-mile network between fulfilment centres, sort centres and delivery stations.

"This is a a major milestone for us," Andreas Marschner, Amazon's ( AMZN ) Vice President of Amazon Worldwide Operations Sustainability, told Reuters. "Decarbonizing the heavy goods sector is the most challenging part of the transportation space."

This order is part of Amazon's ( AMZN ) commitment to hit net-zero carbon emissions across its operations by 2040. It is also the largest electric truck order yet for the Mercedes-Benz Trucks brand, Daimler said.

Aside from a price tag far above diesel truck equivalents, logistics companies have struggled to find electric trucks that have enough range to handle demanding delivery routes and the charging infrastructure to keep them on the road.

The 40-ton eActros 600 has a range of 500 km (311 miles) that Marschner said makes it adaptable to Amazon's ( AMZN ) delivery network.

But he added that Amazon ( AMZN ) is supporting the trucks' roll-out by building a 360 kilowatt fast charger network on its own sites, which can charge a truck from 20% to 80% in less than an hour, "which is compatible also with legal driver breaks."

He said that efforts to boost charging infrastructure in the European Union and the United Kingdom are still in early stages and Amazon ( AMZN ) is working with charging companies and regulators to speed up investments.

"The major transportation corridors in the UK and Germany are still very limited with public charging and high-capacity charging we would need for trucks," Marschner said. "This is a challenge these days as it reduces the ability to use these assets."