Belgian Defense Minister Ludivine Dedonder and Foreign Minister Hadja Lahbib said they would raise the issue with Ukraine at the earliest opportunity, Le Soir daily reported citing sources in the know.
Belgium has been supplying heavy weapons to Ukraine on condition that they will only be used to defend the Ukrainian territory, a source familiar with the matter told the newspaper.
The Russian military said a sabotage and reconnaissance group entered the western Russian region of Belgorod on May 22, killing a civilian and wounding 13 others. Russian troops killed more than 70 militants. A Polish armed group confirmed on Sunday that it took part in the raid.
US Media reported Saturday, citing US officials familiar with intelligence findings, that Ukrainian militants were armed with Belgian and Czech rifles and at least one AT-3 anti-tank weapon, which is used by US and allied troops. The Ukrainians drove mine-resistant MRAP armored vehicles donated to Ukraine by the US and Poland.