UNITED NATIONS - Russian President Vladimir Putin's escalation of the war in Ukraine shows that he is losing control, Prime Minister Justin Trudeau said Wednesday as he condemned his nuclear threats and decision to mobilize some reservists in the ongoing invasion.

“Putin was wrong and he is right now failing and flailing in his response to the situation,” Trudeau told reporters in New York, where he was taking part in the United Nations General Assembly.

Ukraine's seven-month fight against the aggressions of Russia has been a dominant theme of the global gathering, where Ukrainian President Volodymyr Zelenskyy addressed the global gathering by video earlier Wednesday.

Zelenskyy insisted his country would prevail in repelling Russia's attack and forcing its troops out.

That was just hours after Putin announced he would mobilize some reservists in what is the largest military conflict in Europe since the Second World War.

Zelenskyy told the United Nations that decision suggests Putin is not serious about negotiating an end to the conflict.

Trudeau said the recent moves suggest Putin knows things are not going his way.

“He is first of all having to move towards at least a partial conscription in Russia, which is a step closer to admitting what he has not wanted to admit to Russians - that this is a war that he has launched unjustifiably against a neighbour - is an example of things not going to his plan,” Trudeau said.

Trudeau said Canada will continue to strengthen its sanctions related to the Russian invasion and send military aid to Ukraine. He noted Canada has been involved in training Ukrainian armed forces for years and that Ukraine has asked for ammunition.

He also said Canada would keep contributing humanitarian assistance, including measures to respond to the global food crisis sparked by the invasion.

“We are going to continue to stand for the principles that matter so deeply to Canadians and people all around the world with absolute firmness and solidarity with people in Ukraine and continue to encourage and be there for countries, particularly for countries in the global South who are facing difficult times as they too stand against Russia,” he said.

Foreign Affairs Minister Melanie Joly said Canada is especially focused on ensuring the global coalition of countries united against Russia remains healthy and intact.

“Obviously, what Ukraine wants from Canada is always more support on the financial side and more heavy artillery,” she said.

“We've done a lot already. But we need to do more. And we'll do more.”

Meanwhile, Canada's environment minister said the climate crisis has everyone's attention at the United Nations, even as concern mounts about Russia's war on Ukraine.

Steven Guilbeault, who accompanied Trudeau for leader-level meetings at the UN General Assembly, said Wednesday climate issues have become a top-tier concern for world leaders - and that the federal government is helping to drive that agenda.

Guilbeault said even in Europe, where the threats posed by Russia are ever-present, efforts to arrest climate change are in full swing.

“They want to produce 25 per cent of their electricity by rooftop solar panels by 2030. It's unbelievable,” he said.

“They're making more and more investment. And Canada said we will help Europe in as many ways as we can while maintaining our fight against climate change.”

He also noted that U.S. President Joe Biden, a top draw at Day 2 of the leader-level debates in the assembly hall, recently signed off on the single largest climate-change investment in U.S. history.

“I don't think climate change is being put on the back burner,” he said.

“We live in an era where, regardless of what other important things are happening on the international scene, environmental issues like climate change and biodiversity loss have become international priorities.”

Earlier Wednesday, Trudeau announced Canada will contribute $1.21 billion to an international effort to halt the spread of infectious but treatable diseases.

Trudeau made the announcement in New York at a pledging conference for the project, known as the Global Fund to Fight AIDS, Tuberculosis and Malaria.

Canada, a founding supporter of the Global Fund, has already pledged $4 billion since it was founded in 2002 by former banking executive Peter Sands.

The announcement includes an additional $100 million for the fund's COVID-19 response mechanism, which aims to help developing countries mitigate the impact of the pandemic.

The government says the new sum represents a 30 per cent increase over Canada's last contribution and is the country's largest multilateral health investment.

Trudeau was also meeting Caribbean partners to discuss the ongoing crisis in Haiti, where relentless waves of gang violence have persisted through the summer, killing hundreds of people.

Bob Rae, Canada's ambassador to the UN, said he recently visited the country to see the chaos for himself. The gangs have even taken over the courthouse in the capital city of Port-au-Prince, he said.

“We're not going to declare … that we've got a magic solution. That's not how it works,” Rae said.

“We need to learn from some of the mistakes in the past where interventions happened that didn't have the full support of the Haitian people. And we need to make sure that we're working with the people of Haiti.”

That's easier said than done in a country that's being run by a provisional government, he added.

“We're going to try to play as constructive a role as we can. We all know that there's going to be more required.”

This report by The Canadian Press was first published Sept. 21, 2022.

- With files from The Associated Press