UN Secretary General Ban Ki-moon called Russia's President Vladimir Putin today and afterwards said he still thought a negotiated solution to the crisis in Ukraine was possible.
But he warned that the aggressive rhetoric surrounding the dispute over control of Crimea could still lead to disaster and said Ukraine's sovereignty and borders should be respected.
"I urge all concerned to avoid provocation and hasty decisions in the coming days," Ban told reporters at United Nations headquarters in New York after his call to Putin.
"We discussed the need to work towards a durable and fair political solution. We agreed to remain in close touch," he said.
Ban expressed caution about the referendum that will be held on Sunday in the Ukrainian region of Crimea, in which voters are expected to back a split from Kiev in favor of joining Russia.
"What I am concerned about is that, as I said, there should be no such hasty measures and decisions which may impact the sovereignty, unity and territorial integrity of Ukraine," he warned.
The United States and the European Union have taken Ukraine's side in the dispute and are preparing to impose sanctions on Russian figures on Monday if Moscow does not back down.
But Ban warned both sides against tough rhetoric.
"It is clear that we are at a crossroads," he said.
"If positions continue to harden and rhetoric continues to sharpen, there is great risk of a dangerous downward spiral."
He added: "Although it has so far proven elusive, the path towards a peaceful resolution of the crisis is still open. Our duty is to seize it.
