World leaders came together, virtually, on Monday to mark the 75th anniversary of the United Nations, as the deadly coronavirus pandemic challenges the effectiveness and solidarity of the 193-member world body.

As Covid-19, which emerged in China late last year, began to spread around the world, forcing millions of people to shelter at home and dealing a devastating economic blow, countries turned inward and diplomats say the United Nations struggled to assert itself.

UN secretary-general Antonio Guterres told Reuters that the pandemic has exposed the world’s fragilities. He told world leaders on Monday that they need to work together at a time when there is a surplus of multilateral challenges and deficit of solutions.

The 15-member Security Council took months to back a call by Guterres for a global ceasefire – to allow countries to focus on fighting Covid-19 – due to bickering between the world’s biggest powers: China and the United States.

The 193-member UN General Assembly only adopted an omnibus resolution on a “comprehensive and coordinated response” to the pandemic earlier this month, and it was not by consensus. The US and Israel voted no.

A $10.3 billion UN appeal to fund fighting the pandemic in vulnerable and low-income countries is only a quarter funded. Guterres now has taken a lead in pushing to make sure any vaccine for the coronavirus is made available to everyone globally.

A senior European diplomat, speaking on condition of anonymity, said the General Assembly should have acted months ago, but “we were all hampered by, and hit, by the Covid-19”.

After New York was hit hard by the coronavirus, UN member states had to decide how to work virtually, which they did for several months before resuming some in-person meetings.

“We all suffered from the fact that we couldn’t meet… A lot of attention was paid to process more than substance unfortunately,” said the European diplomat. “I wouldn’t put the blame on the UN, it’s the member states that have to be more positive.”

Monday’s event comes ahead of the annual meeting of world leaders at the UN, which starts on Tuesday with no presidents or PMs physically present in New York. All statements have been pre-recorded and will be broadcast in the General Assembly hall.