Moscow’s intervention in Ukraine and its continued support for rebels in the east of the country is not “not a wise course for Russia”, former U.K. foreign secretary and leading government politician William Hague has told CNBC.

“If Russia continues on this course of the last few days there will be a further grave deterioration in relations between the European Union and Russia,” he told CNBC’s Worldwide Exchange.

Fighting in the eastern Donbass region of Ukraine between government forces and Russian-backed separatists has increased in recent weeks, shattering an already-weak ceasefire. According to local media, at least nine Ukrainian servicemen were killed and some 30 wounded in the war zone on Jan. 26, bringing the death toll in the region to some 10,000 people on both sides.

Hague, who was foreign secretary at the time the Ukraine crisis began last February, told CNBC that by intervening in the Donbass dispute, the Kremlin was still “trying to prevent the Ukraine from operating as a normal country.”

The Russian president has a great regret at the demise of the Soviet Union, Hague added, and Putin “still has the view that Russia as a great power… has a view that there is a sphere of influence, that you are allowed to exert enormous influence over the policies, including the domestic policies, of neighbouring countries.”

Hague added said that he had always been prepared for the situation in the region to be a long-term conflict and that “sanctions are having quite a big effect.”

Putin continues to claim aggression in the east of Ukraine is the fault of the Kiev government, which he says is a puppet of the West. However, the international community is unconvinced. Earlier this week, NATO Secretary General Jens Stoltenberg dismissed an accusation made by Putin on Monday that NATO forces were fighting alongside Ukrainian armed forces as “nonsense,” adding that the only foreign forces in Ukraine are Russian.

Crucial talks are taking place between Hague’s successor, Philip Hammond, and other European foreign ministers tomorrow, where the next course of action on Russia will be discussed.

If they decide to increase sanctions, it will come at a desperate time for Russia’ economy after U.S. ratings agency Standard & Poor’s downgraded the country’s bonds to “junk” status Monday night. Former UK ambassador to Russia, Sir Andrew Wood, told CNBC on Tuesday that Putin needed a “miracle” to turn around the country’s economy.

“He (Putin) fears to appear weak. He’s actually presented himself with an insoluble problem,” Wood told CNBC.

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