US President Joe Biden is ready to make the case to world leaders at the UN General Assembly that Russia’s “naked aggression” in Ukraine is an affront to what the international body stands for.

Mr Biden is looking to rally allies to stand firm in backing the Ukrainian resistance to Vladimir Putin.

The American leader, during his time at the UN General Assembly, also plans to meet Prime Minister Liz Truss, announce a global food security initiative and press allies to meet an 18 billion dollar (£15 billion) target to replenish the Global Fund to Fight Aids, tuberculosis and malaria.

However, White House officials say the crux of the president’s visit to the UN this year would be a full-throated condemnation of Russia as its brutal war nears the seven-month mark.

White House national security adviser Jake Sullivan said ahead of Mr Biden’s address: “He’ll offer a firm rebuke of Russia’s unjust war in Ukraine and make a call to the world to continue to stand against the naked aggression that we’ve seen these past several months.

“He will underscore the importance of strengthening the United Nations and reaffirm core tenets of its charter at a time when a permanent member of the Security Council has struck at the very heart of the charter by challenging the principle of territorial integrity and sovereignty.”

Mr Biden is confronting no shortage of difficult issues as leaders gather in New York this year.

In addition to the Russian war in Ukraine, European fears that a recession could be just around the corner are heightened.

Concerns grow by the day that time is running short to revive the Iran nuclear deal, while fears are rising over China’s sabre-rattling on Taiwan.

When he addressed last year’s General Assembly, Mr Biden focused on broad themes of global partnership, urging world leaders to act with haste against the coronavirus, climate change and human rights abuses.

And he offered assurances that his presidency marked a return of American leadership to international institutions following Donald Trump’s “America First” foreign policy.

But one year later, global dynamics have dramatically changed.

Stewart Patrick, senior fellow and director of the Global Order and Institutions Programme at the Washington think tank Carnegie Endowment for International Peace, wrote in an analysis that Mr Biden’s task this year is “immense” compared to his first address to the UN as president.

“Last year, the US leader won easy plaudits as the ‘anti-Trump’, pledging that ‘America was back’,” Mr Patrick said.

“This year demands more. The liberal, rules-based international system is reeling, battered by Russian aggression, Chinese ambitions, authoritarian assaults, a halting pandemic recovery, quickening climate change, scepticism of the UN’s relevance, and gnawing doubts about American staying power.”

Beyond international diplomacy, the president is also tackling some domestic issues. This year’s gathering comes less than seven weeks before pivotal mid-term elections in the United States.

Shortly after arriving in Manhattan on Tuesday night, Mr Biden spoke at a Democratic National Committee fundraiser for about 100 participants that raised nearly two million dollars (£1.75 million), and he is set to hold another fundraiser on Thursday before heading back to Washington.

Mr Biden’s visit to the UN also comes as his administration’s efforts to revive the 2015 Iran nuclear deal appear stalled.

The deal brokered by the Obama administration – and scrapped by Mr Trump in 2018 – provided billions of dollars in sanctions relief in exchange for Iran’s agreement to dismantle much of its nuclear programme and open its facilities to extensive international inspection.

This year’s UN gathering is back to being a full-scale, in-person event after two years of curtailed activity due to the pandemic.

In 2020, the in-person gathering was cancelled and leaders instead delivered pre-recorded speeches; last year was a mix of in-person and pre-recorded speeches. Mr Biden and first lady Jill Biden were set to host a leaders’ reception on Wednesday evening.

China’s President Xi Jinping opted not to attend this year’s UN gathering, but his country’s conduct and intentions will loom large during the leaders’ talks.

Last month, the UN human rights office raised concerns about possible “crimes against humanity” in China’s western region against Uighurs and other largely Muslim ethnic groups.

Beijing has vowed to suspend cooperation with the office and blasted what it described as a Western plot to undermine China’s rise.

Meanwhile, China’s government on Monday said Mr Biden’s statement in a CBS 60 Minutes interview that American forces would defend Taiwan if Beijing tried to invade the self-ruled island was a violation of US commitments on the matter, but it gave no indication of possible retaliation.