Authorities in Luhansk that five people were killed and 15 injured by overnight artillery strikes. Three were killed in Donetsk as a result of clashes, the city's government said.
Territory between the cities has seen intensified fighting as government troops try to gain control over the area where a Malaysia Airlines plane was downed earlier this month.
Dutch and Australian police set off for the crash site today morning in a convoy of 20 cars, aiming to secure the area so that investigations can continue and any remaining bodies can be recovered.
Rebels accuse government troops of deploying artillery against residential areas. Authorities deny that charge, but also complain of insurgents using apartment blocks as firing positions.
The US State Department yesterday released satellite images that it says back up its claims that rockets have been fired from Russia into eastern Ukraine and heavy artillery for separatists has also crossed the border.
Russian Foreign Minister Sergey Lavrov dismissed the claims today during a televised press conference, asking "why it took ten days" before the US released the images.
The images could not be independently verified by The Associated Press.
Lavrov said he is expecting OSCE observers to arrive at the Russian-Ukrainian border "in the coming days." He said they would see that accusations rebels are travelling freely into Ukraine from Russia are false.
