Russian and Syrian jets have flown their first mission together over Syria, according to Russia's defence ministry.
A pair of Syrian MiG-29 warplanes escorted two Su-25 jets during Thursday’s mission.The defence ministry released a video showing the Russian ground attack aircraft taking off from Hemeimeem air base and being joined by the MiGs.
Russia has been flying combat missions in Syria since 30 September.
It insists it is targeting IS forces but has been accused of also attacking rebel groups trying to overthrow President Assad.
Meanwhile, people on the verge of starvation in the besieged Syrian city of Madaya have received 44 more truckloads of food and aid, as the UN chief said using starvation as a weapon was a "war crime".
"All sides - including the Syrian government which has the primary responsibility to protect Syrians - are committing this and other atrocious acts prohibited under international humanitarian law," said Ban Ki-moon.
Many people in the town of 40,000 have been struggling to survive amid a siege by government forces, with some reportedly forced to eat leaves and pets.
Mr Ban added: "UN teams have witnessed scenes that haunt the soul. The elderly and children, men and women, who were little more than skin and bones: gaunt, severely malnourished, so weak they could barely walk, and utterly desperate for the slightest morsel."
A separate convoy of 17 trucks also arrived in the besieged towns of Fuaa and Kafraya, according to the International Red Cross. Those towns are being surrounded by rebel troops.
The UK, US and France have called for an emergency meeting of the UN Security Council on Friday to discuss speeding up delivery of the supplies and ending the sieges.
Fresh negotiations over finding an end to the civil war are planned for 25 January in Geneva.