An airport in the eastern Donetsk region of Ukraine was attacked on Friday.
An explosion at Kramatorsk airport destroyed a military helicopter and surveillance airplane according to the owner of the airfield.
Ukranian authorities said it was an “act of sabotage” by pro-Russian separatists. Ukrainian army troops had taken back control of the airport last week after it was occupied by militiamen.
Some 100 kilometres away in Slovyansk, the self-proclaimed mayor admitted separatists may be holding a group of OSCE monitors.
“The sign OSCE (Organisation for Security and Cooperation in Europe) does not mean protection for an officer of the (army) General Headquarters. We found an employee of the army headquarters. After an investigation we will decide what we are to do,” Vyacheslav Ponomaryov said.
The Ukrainian government said it had ruled out an assault on Slovyansk to avoid casualties.