That barely-there ceasefire in Ukraine has never looked shakier, as Donetsk comes under the heaviest shelling in months.  Observers say it appears to be both government forces and Russian-backed rebels doing the shooting.

More than 4,000 people have died in the conflict in Eastern Ukraine, which began when pro-Russian groups took up arms against the new, pro-western central government in Kiev earlier this year.  Donetsk Airport got another pounding and shells fell closer to the edges of the city.  And if witnesses and monitors are correct, it’s going to get worse with the arrival of unmarked convoys of military supplies near the city.

“The most recent reports by the OSCE (Organization for Security and Co-operation in Europe) Special Monitoring Mission in Ukraine about convoys in separatist held areas with substantial amounts of heavy weapons, tanks and troops without insignia moving westwards represent a very worrying development,” said the European Union’s foreign policy chief Federica Mogherini.

Kiev accuses Moscow of sending a column of 32 tanks and truckloads of troops into the rebellious east to support the pro-Russian rebels in recent days.  The Kremlin has consistently denied such accusations.