President Joe Biden declared in his final address to the U.N. General Assembly on Tuesday that the U.S. must not retreat from the world, as Israel and Hezbollah militants in Lebanon edged toward all-out war and Israel's bloody operation against Hamas in Gaza neared the one-year mark.

Biden used his wide-ranging address to speak to a need to end the Middle East conflict and the 17-month-old civil war in Sudan and to highlight U.S. and Western allies' support for Kyiv since Russia invaded Ukraine in February 2022. He also raised concern over artificial intelligence and its potential to be used for repression.

His appearance before the international body offered Biden one of his last high-profile opportunities as president to make the case to keep up robust support for Ukraine, which could be in doubt if former President Donald Trump defeats Vice President Kamala Harris in November. Biden insisted that despite global conflicts, he remains hopeful for the future.

“I've seen a remarkable sweep of history," Biden said. “I know many look at the world today and see difficulties and react with despair but I do not.”

“We are stronger than we think” when the world acts together, he added.

Biden came to office promising to rejuvenate U.S. relations around the world and to extract the U.S. from “forever wars” in Afghanistan and Iraq that consumed American foreign policy over the last 20 years.

“I was determined to end it, and I did,” Biden said of the Afghanistan exit, calling it a “hard decision but the right decision.” He acknowledged that it was "accompanied by tragedy” with the deaths of 13 American troops and hundreds of Afghans in a suicide bombing during the chaotic withdrawal.

But his foreign policy legacy may ultimately be shaped by his administration's response to two of the biggest conflicts in Europe and the Middle East since World War II.

“There will always be forces that pull our countries apart,” Biden said, rejecting “a desire to retreat from the world and go it alone.” He said, "Our task, our test, is to make sure that the forces holding us together are stronger than the forces pulling us apart.”

The Pentagon announced Monday that it was sending a small number of additional U.S. troops to the Middle East to supplement the roughly 40,000 already in the region. All the while, the White House insists Israel and Hezbollah still have time to step back and de-escalate.

“Full scale war is not in anyone's interest,” Biden said, and despite escalating violence, a diplomatic solution is the only path to peace.

Biden had a hopeful outlook for the Middle East when he addressed the U.N. just a year ago. In that speech, Biden spoke of a “sustainable, integrated Middle East” coming into view.

At the time, economic relations between Israel and some of its Arab neighbors were improving with implementation of the Abraham Accords that Israel signed with Bahrain, Morocco and the United Arab Emirates during the Trump administration.

Biden's team helped resolve a long-running Israel-Lebanon maritime dispute that had held back gas exploration in the region. And Israel-Saudi normalization talks were progressing, a game-changing alignment for the region if a deal could be landed.

“I suffer from an oxymoron: Irish optimism,” Biden told Israeli Prime Minister Benjamin Netanyahu when they met on the sidelines of last year's U.N. gathering. He added, "If you and I, 10 years ago, were talking about normalization with Saudi Arabia ... I think we'd look at each other like, Who's been drinking what?'”

Eighteen days later, Biden's Middle East hopes came crashing down. Hamas militants stormed into Israel killing 1,200, taking some 250 hostage, and spurring a bloody war that has killed more than 41,000 Palestinians in Gaza and led the region into a complicated downward spiral.

Now, the conflict is threatening to metastasize into a multi-front war and leave a lasting scar on Biden's presidential legacy.

Israel and Hezbollah traded strikes again Tuesday as the death toll from a massive Israeli bombardment climbed to nearly 560 people and thousands fled from southern Lebanon. It's the deadliest barrage since the 2006 Israel-Hezbollah war.

Israel has urged residents of southern Lebanon to evacuate from homes and other buildings where it claimed Hezbollah has stored weapons, saying the military would conduct “extensive strikes” against the militant group.

Hezbollah, meanwhile, has launched dozens of rockets, missiles and drones into northern Israel in retaliation for strikes last week that killed a top commander and dozens of fighters. Dozens were also killed last week and hundreds more wounded after hundreds of pagers and walkie-talkies used by Hezbollah militants exploded, a sophisticated attack that was widely believed to have been carried out by Israel.

Israel's leadership launched its counterattacks at a time of growing impatience with the Iranian-backed Hezbollah's persistent launching of missiles and drones across the Israel-Lebanon border after Hamas started the war with its brazen attack on Oct. 7.

Biden reiterated his call on the parties to agree to a cease-fire and hostage release deal, saying it's time to "end this war" — even as hopes for such a deal are fading as the conflict drags on.

Biden, in his address, called for the sustainment of Western support for Ukraine in its war with Russia. Biden helped galvanize an international coalition to back Ukraine with weapons and economic aid in response to Russian President Vladimir Putin's February 2022 assault on Ukraine.

“We cannot grow weary," Biden said. "We cannot look away.”

Biden has managed to keep up American support in the face of rising skepticism from some Republican lawmakers — and Trump — about the cost of the conflict.

At the same time, Ukrainian President Volodymyr Zelenskyy is pressing Biden to loosen restrictions on the use of Western-supplied long-range missiles so that Ukrainian forces can hit deeper in Russia.

So far Zelenskyy has not persuaded the Pentagon or White House to loosen those restrictions. The Defense Department has emphasized that Ukraine can already hit Moscow with Ukrainian-produced drones, and there is hesitation on the strategic implications of a U.S.-made missile potentially striking the Russian capital.

Putin has warned that Russia would be “at war” with the United States and its NATO allies if they allow Ukraine to use the long-range weapons.

Biden and Harris are scheduled to hold separate meetings with Zelenskyy in Washington on Thursday. Ukrainian officials were also trying to arrange a meeting for Zelenskyy with Trump this week.

The president also sounded an alarm about the rapid advances in artificial intelligence development, particularly around disinformation, respect for human life and the potential exploitation by totalitarian powers. He told the world leaders, "There may well be no greater test of our leadership than how we deal with A.I."

“We must make certain that the awesome capabilities of A.I. will be used to uplift and empower everyday people, not to give dictators more powerful shackles on the human spirit," he added.

Biden struck a wistful tone in his remarks, peppering his speech with references to his first time attending the General Assembly more than 50 years ago, and quoting Irish poetry.

Biden held up his decision to step aside up as an instructive moment as he addressed a gathering that has no small share of totalitarian and nondemocratic leaders.

“Some things are more important than staying in power," Biden said. "It's your people that matter the most. Never forget, we are here to serve the people. Not the other way around.”