Pro-Russian rebels in eastern Ukraine have rejected a previously signed peace deal and launched a new offensive against Ukrainian government troops.

The latest violence disrupts recent European attempts to mediate an end to the fighting.

The main separatist leader in the rebellious Donetsk region has vowed to push Ukrainian soldiers out of the area, saying insurgents won't take part in any more ceasefire talks.

Another rebel went even further, saying they will not abide by a peace deal signed in September.