GENEVA (AFP) - UN Secretary General Ban Ki-moon called Monday on Russia to avoid actions that might worsen the situation in crisis-hit Ukraine.

"I urge the Russian Federation to refrain from any acts and rhetoric that could further escalate the situation," Mr Ban said to the press ahead of a scheduled meeting with Russian Foreign Minister Sergei Lavrov.

"It is critical to ensure full respect for and the preservation of Ukraine's independence, unity, sovereignty and territorial integrity," leaders told reporters on the sidelines of the UN Human Rights Council in Geneva.

"It is now of the utmost importance to restore calm and to de-escalate tensions immediately through dialogue," he said, urging Russia to "start to engage constructively and through peaceful means with Ukraine".

Mr Ban said he and Mr Lavrov would discuss "how the UN can work together with Russian Federation and Ukraine authorities, and the OSCE (Organisation for Security and Cooperation in Europe), EU and other partners to first of all de-escalate the situation".

In a phone conversation with President Vladimir Putin on Saturday, Mr Ban said he had urged the Russian leader to engaged "constructively and directly with Ukraine authorities."

"It is important that both sides should lower their temperature," he insisted.