The head of the European Union Military Committee (EUMC) has expressed doubts about whether Ukraine can regain any territory lost in the war with Russia with its current capacities.

"It remains questionable whether Ukraine's full sovereignty can be restored with the resources available," Robert Brieger, told German newspaper Die Welt. 

The EUMC, the EU's highest military body, is composed of the bloc's 27 member states. 

Brieger further said he would be "cautious to expect a breakthrough of the Ukrainian forces through the Russian defense lines."