European Commission head Jean-Claude Juncker told Russia on Thursday that the "only way" the 28-nation bloc will lift its economic sanctions on Moscow is if the Kremlin fully implements a peace deal for Ukraine.

European Commission head Jean-Claude Juncker told Russia on Thursday that the "only way" the 28-nation bloc will lift its economic sanctions on Moscow is if the Kremlin fully implements a peace deal for Ukraine.

"The next step is clear, full implementation of the agreement -- no more, no less. This is the only way to begin our conversation and the only way to lift the economic sanctions that have been imposed," he said at Russia's main economic forum in Saint Petersburg.

Juncker is set to hold talks with President Vladimir Putin later Thursday in the first such meeting in Russia since the EU slapped sanctions on Moscow over the Ukraine conflict in 2014.

The meeting in Russia's second city comes just weeks before the 28-nation EU is set to vote on extending the sanctions that have helped push Russia's economy into recession.

Putin will also meet UN chief Ban Ki-moon alongside the world body's envoy on Syria Staffan de Mistura, as he seeks to recast Moscow as a more stable partner for the West and bolster his country's flagging economy.

The EU has tied the lifting of punishing economic sanctions that have hit Russia's financial sector to the implementation of an deal brokered by the leaders of France and Germany in February 2015 to end the pro-Russian uprising in east Ukraine.

But the accord has stalled as the violence rumbles on.

Despite the frosty relations, Juncker insisted he had come to Russia to try to improve relations.

"If our relationship today is troubled and marked by mistrust, it is not broken beyond repair. We need to mend it, and I believe we can," he said in his speech.