Nineteen Ukrainian troops have died battling rebels in a strategic town east of Donetsk, UK Wired News reported Thursday.
Ukraine's National Guard has sent extra mortars and anti-tank weapons to the volunteers fighting the pro-Russian separatists in Ilovaisk, officials say.
Ukrainian customs officials are reported to be checking the cargo of some Russian aid lorries at the border.
The aid is intended for civilians in the besieged city of Luhansk, but the convoy has been delayed for days.
The Russian convoy totals 270 lorries. They have been parked near the Russian town of Kamensk-Shakhtinsky since leaving the Moscow region on 12 August, and are said to be carrying 2,000 tonnes of aid.