Ukraine forces suffer major setbacks as pro-Russian rebels seize eastern towns

Ukrainian forces have suffered a series of setbacks in Luhansk and Donetsk as pro-Russian separatists continue to seize one town after the other in the eastern part of the country.

The rebels have captured nearly 700 soldiers since the start of the rebel offensive, according to officials.

Ukraine's defence minister, Valery Heletey, said it was now fighting a "great war" with Russia in which tens of thousands could die, the BBC reported.

Heletey posted on his Facebook page that the pro-Russian rebels had been defeated, forcing Russia to commence a full-scale invasion of the region with regular forces, the report said.

The military, earlier, said that government forces had to retreat from Luhansk airport after being faced with a series of attacks by Russian tanks.

At least 2,600 people have lost their lives in eastern Ukraine since fighting began in April over Russia's annexation of Ukraine's southern Crimea peninsula in March.