UN chief Antonio Guterres warned nations Monday that he fears the likelihood of further escalation in the Russia-Ukraine conflict means the world is heading towards a "wider war."

The secretary-general laid out his priorities for the year in a gloomy speech to the United Nations General Assembly that focused on Russia's invasion, the climate crisis and extreme poverty.

"We have started 2023 staring down the barrel of a confluence of challenges unlike any in our lifetimes," he told diplomats in New York.

Guterres noted that top scientists and security experts had moved the "Doomsday Clock" to just 90 seconds to midnight last month, the closest it has ever been to signaling the annihilation of humanity.

The secretary-general said he was taking it as a warning sign.

"We need to wake up -- and get to work," he implored, as he read out a list of urgent issues for 2023.

Top of the list was Russia's war in Ukraine, which is approaching its one-year anniversary.

"The prospects for peace keep diminishing. The chances of further escalation and bloodshed keep growing," he said.

"I fear the world is not sleepwalking into a wider war. I fear it is doing so with its eyes wide open."

Guterres referenced other threats to peace, from the Israeli-Palestinian conflict to Afghanistan, Myanmar, the Sahel and Haiti.

"If every country fulfilled its obligations under the (UN) Charter, the right to peace would be guaranteed," he said.

He added it is "time to transform our approach to peace by recommitting to the Charter -- putting human rights and dignity first, with prevention at the heart."

More broadly, Guterres denounced a lack of "strategic vision" and a "bias" of political and business decision-makers towards the short term.

"The next poll. The next tactical political maneuver to cling to power. But also the next business cycle -- or even the next day's stock price.

"This near-term thinking is not only deeply irresponsible -- it is immoral," he added.

Stressing the need to act with future generations in mind, the secretary-general repeated his call for a "radical transformation" of global finance.

"Something is fundamentally wrong with our economic and financial system," Guterres said, blaming it for the increase in poverty and hunger, the growing gap between rich and poor, and the debt burden of developing countries.

"Without fundamental reforms, the richest countries and individuals will continue to pile up wealth, leaving crumbs for the communities and countries of the Global South," he