President Joe Biden has used his first address before the UN General Assembly (UNGA) to declare that the world stands at an "inflection point in history" and must move quickly to address the festering issues of the Covid-19 pandemic, climate crisis, and human rights abuse.

Amid growing China tensions Biden also declared on Tuesday the US is "not seeking a new Cold War."

Without mentioning China directly, Biden acknowledged increasing concerns about rising tensions between the two nations. 

But he said, "We are not seeking a new Cold War or a world divided into rigid blocs."

'Ended 20 years of conflict in Afghanistan'

The president noted his decision to end America's longest war last month, in Afghanistan, and set the table for his administration to shift US attention to intensive diplomacy with no shortage of crises facing the globe. 

He said he is driven by a belief that "to deliver for our own people, we must also engage deeply with the rest of the world."

"We've ended 20 years of conflict in Afghanistan," Biden said. 

"And as we close this period of relentless war, we're opening a new era of relentless diplomacy of using the power of our development aid to invest in new ways of lifting people up around the world."

But Biden was facing a healthy measure of skepticism from allies during his week of high-level diplomacy. 

The opening months of his presidency have included a series of difficult moments with friendly nations that were expecting greater cooperation from him following four years of Donald Trump's "America first" approach to foreign policy.

Out of sync with allies

Eight months into his presidency, Biden has been out of sync with allies on the chaotic ending to the US war in Afghanistan. 

He has faced differences over how to go about sharing coronavirus vaccines with the developing world and over pandemic travel restrictions. 

Biden also finds himself in the midst of a fresh diplomatic spat with France, the United States' oldest ally, after announcing plans — along with Britain — to equip Australia with nuclear-powered submarines. 

READ MORE: EU rallies behind France as tensions rock Western alliance over subs deal

Biden also scheduled to meet with British Prime Minister Boris Johnson on Tuesday at the White House and invited the prime ministers of Australia, India, and Japan — part of a Pacific alliance known as "the Quad" — to Washington on Friday. 

In addition to the gathering of Quad leaders, Biden will sit down for one-on-one meetings with Indian Prime Minister Narendra Modi and Japanese Prime Minister Yoshihide Suga.

Iran nuclear talks

Biden told the UNGA that the United States would return to the Iranian nuclear deal in "full" if Tehran does the same.

He said the United States was "working" with China, France, Russia, Britain and Germany to "engage Iran diplomatically and to seek a return to" the Joint Comprehensive Plan of Action, which America left in 2018.

"We're prepared to return to full compliance if Iran does the same," he added.

Mideast conflict 

Biden said that a sovereign and democratic Palestinian state is the "best way" to ensure Israel's future.

"We must seek a future of greater peace and security for all people of the Middle East," Biden said.

"The commitment of the United States to Israel's security is without question and our support for an independent Jewish state is unequivocal," he said.

"But I continue to believe that a two-state solution is the best way to ensure Israel's future as a Jewish democratic state, living in peace alongside a viable, sovereign and democratic Palestinian state," he said.

"We're a long way from that goal at this moment but we should never allow ourselves to give up on the possibility of progress."