Updated

The Russian defense ministry says a Russian colonel who worked as a military adviser in the government-controlled part of the Syrian city of Aleppo has died in rebel shelling.

The fatality marks Russia's third casualty this week, after two nurses were killed in a rocket attack on a makeshift Russian military hospital in Aleppo.

The ministry said in a statement on Wednesday that Col. Ruslan Galitsky was wounded in rebel shelling of a government-controlled neighborhood several days earlier and has died of wounds.

The Syrian government and its ally Russia have rejected a cease-fire for the war-torn city, keeping up the military offensive amid rebel retreats and massive displacement of Aleppo civilians.