KIEV, Jan 27 - Parliament on Tuesday approved a statement defining Russia as an "aggressor state," which deputies said could pave the way for consequences under international law, and called for more international aid and stronger sanctions on Russia, Reuters reported.

"Legal recognition as an aggressor state entails consequences as provided for under 1974 UN resolution and the UN charter," Radical Party leader Oleh Lyashko, a member of the governing coalition, said ahead of the vote.

Parliament also voted to define separatist self-styled "Republics" in east Ukraine as "terrorist organizations" and to appeal to the international community for additional non-lethal military aid and stronger sanctions against Russia.

Meanwhile, pro-Russian separatist forces said on Tuesday they had pushed Ukrainian government troops out of two districts on the outskirts of their main stronghold Donetsk, and their aim was to expand their control to the entire region.

A rebel advance launched last week has dashed a five-month truce, reignited a war that has killed more than 5,000 people and brought threats of new sanctions on Moscow, which NATO accuses of backing the separatists with money, arms and troops.

The separatists say their initial objective is to drive back government forces to push artillery out of range of their cities and improve their grip on their main strongholds.

The new rebel advance has brought calls from the United States and Europe for tighter sanctions against Moscow, which Kiev and NATO say has regular serving troops to fight on behalf of the rebels. President Barack Obama has said Washington would consider all steps short of military action to isolate Russia.

European Union leaders asked their foreign ministers to consider possible new sanctions on Russia in response to the rebel offensive. A final decision to impose them is likely to be left to a summit next month.

The separatists, fighting for the independence of an area dubbed "New Russia" by the Kremlin, now control the capitals and around half of the territory of Donetsk and Luhansk provinces, together known as the Donbass region.

Mariupol is by far the biggest city in the Donbass still held by the government, and capturing the port city would give the rebels important strategic advantages. Any such battle could involve urban warfare on a scale unprecedented in the conflict.

The rebels halted at the gates of Mariupol during their last big advance in August that forced Kiev into a ceasefire. (rt/ez)