United Nations Secretary General Antonio Guterres on Friday said it would be “catastrophic” if the prevailing tensions between Russia and Ukraine lead to a war, reported AFP.

In his opening remarks at the Munich Security Conference Opening Segment, Guterres noted the amassing of Russian troops along Ukraine’s borders.

“I am deeply concerned about heightened tensions and increased speculation about a military conflict in Europe,” he said.

Since early this year, Russia has amassed over 1 lakh troops at the Ukrainian border. Reports also said that 30,000 more are engaged in exercises in Belarus, close to its border with Ukraine. The two countries have been engaged in a conflict since 2014 when Russia annexed Ukraine’s Crimean Peninsula and backed separatist rebellions in the country’s eastern regions of Donetsk and Luhansk.

Over the last week, Russia has claimed to have pulled back some of its troops, but the United States and the North Atlantic Treaty Organization have maintained that Kremlin was still sending soldiers to Ukraine’s borders.

On Friday, Guterres said he still feels that there may not be a war. “But if it did, it would be catastrophic,” he said.

The United Nations Secretary General underlined that there is no alternative to diplomacy. He said all matters, including the “most intractable” ones, must be addressed through diplomatic frameworks. “And it is high time to seriously de-escalate,” he said.

Guterres also noted that geopolitical divides have continued to grow and deepen. He said that he has often been asked if the world is in a new “Cold War”.

“My answer is that the threat to global security now is more complex and probably higher than at that time,” he said.

US Vice President Kamala Harris, who also spoke at conference, said Russia must show it is serious about diplomacy. Meanwhile, French President Emmanuel Macron called for a “cessation of hostilities”, reported Reuters.