Leaders from around the world are attending the United Nations General Assembly. UN Secretary-General Antonio Guterres warned them on Tuesday that the global state of affairs is "unsustainable" and the level of impunity in the world is "intolerable."

Guterres said: "Wars rage with no clue how they will end. And nuclear posturing and new weapons cast a dark shadow. We are edging towards the unimaginable: a powder keg that risks engulfing the world."

He added that some leaders are trampling on the UN Charter and international law, saying they feel entitled to a "get out of jail free" card.

Guterres cited the war in Ukraine and what he called the "nonstop nightmare" in Gaza, which he said threatens to overwhelm the entire region. He pointed at Lebanon and the fighting between Israeli forces and Hezbollah militants.

US President Joe Biden gave an address, saying he believes it is not too late to stop the violence. Biden said: "Full-scale war is not in anyone's interest. Even if the situation has escalated, a diplomatic solution is still possible."

Biden will leave office in January. He noted what he called the "remarkable sweep of history" he has seen in more than 50 years of public service.