Fighting broke out between the Ukrainian military and pro-Russian separatists in Donetsk, eastern Ukraine this morning
Tanks were seen going towards the city's train station and airport and locals are fleeing, BBC reporters said on Twitter.
The BBC's Will Vernon wrote: "Lots of buses speeding towards #Donetsk train station. Evacuating civilians from station area. Colleague saw dead civilian lying in yard".
Foreign Correspondent Fergal Keane also said: "#Donetsk rebel commander just told us Ukrainian forces attacking around rail station and airport."
#Donetsk Fleeing woman said shell had killed neighbour."We are terrified.We want to leave"— Fergal Keane (@fergalkeane47) July 21, 2014
Tensions between Russia and Kiev have focussed on Donetsk, and Ukrainian President Petro Poroshenko has vowed to retake the city in what Kiev describes as an "anti-terrorist operation" against the separatists.
The airport was at the centre of fighting between Ukrainian armed forces and rebels on May 26, when separatists grounded all flights.
Grabavo village, where the Malaysian Airlines passenger plane flight MH17 was shot down on Thursday, is in the Donetsk region.