HAMBURG (Reuters) - The Organisation for Security and Cooperation in Europe on Friday launched a tender for long-range drones after losing eight such aircraft over eastern Ukraine since it began a monitoring mission there.

“Many of our drones were electronically destroyed or shot down,” OSCE Secretary General Lamberto Zannier told reporters during a two-day ministerial meeting in Hamburg.

He said the group had suspended the use of the drones, which can fly 150 km (93 miles), after the losses, which Russian-based separatists - who are battling Ukrainian troops for control of the Donbass region - were mainly responsible for.

The OSCE, a 57-member human rights and security watchdog, ski has been using unmanned planes to help monitor the lines of conflict and augment the work of over 700 human observers in eastern Ukraine, often providing access to areas where monitors have been blocked.

The OSCE said it had also lost two medium-range and five short-range drones.

Zannier said the OSCE also planned to invest more in other high-tech equipment to aid its work, including motion-activitated mounted camera that can transmit infrared data, as well as commercial satellite imagery.

A spokesman for Schiebel, which made the drones that were shot down, said the firm planned to submit a bid for the tender.