It would be "catastrophic" if the Russia-Ukraine crisis escalated into a war, UN Secretary-General Antonio Guterres told the opening ceremony of the Munich Security Conference on Friday, which Moscow is not attending this year.  

"With a concentration of Russian troops around Ukraine, I am deeply concerned about heightened tensions and increased speculation about a military conflict in Europe," Guterres said.  

If that happened, "it would be catastrophic," he warned. "There is no alternative to diplomacy." 

Guterres said the world is probably a more dangerous place now than during the Cold War.

"I am often asked whether we are in a new Cold War," Guterres said. "My answer is that the threat to global security now is more complex and probably higher than at that time." 

He noted that there were mechanisms for concerned parties to calculate risks and use "back-channels" to prevent crises during the Cold War. 

"Today, many of those systems no longer exist and most of the people trained to use them are no longer here with us," he said. 

"I urge all parties to be extremely careful with their rhetoric. Public statements should aim to reduce tensions, not inflame them," Guterres said. 

Chinese Foreign Ministry spokesperson Wang Wenbin on Friday called on relevant sides to conduct dialogue and negotiations on the basis of the Minsk Agreements, properly address the legitimate security concerns of relevant sides including Russia, and strive for a comprehensive settlement of the Ukraine crisis and other relevant issues. 

Follow the last developments over Ukraine

(With input from AFP)