UN Secretary-General Antonio Guterres warned on Monday that unequal education would quickly divide the planet as he tried to keep the development on the agenda ahead of a week of diplomacy focused on global crises.

The UN chief called a special summit on education a day before the annual General Assembly meeting of world leaders, although a number of key officials, including US President Joe Biden, have announced their arrival in New York for the funeral of Queen Elizabeth II delayed.

“Education is in a deep crisis. Instead of being the great enabler, education quickly becomes the great divide,” Guterres said at the summit.

He warned that the Covid-19 pandemic had had a “devastating impact” on learning, with poor students without technology being particularly disadvantaged and conflict further disrupting schools.

Guterres called on all countries to prioritize increasing spending per student, even amid question marks over the global economy.

In a report earlier this month, the UN Development Program said Covid has set back human progress by five years.

Guterres also called out the Afghan Taliban, who have deprived more than a million teenage girls of their education since Islamist militants returned to power in August 2021.

“I appeal to the authorities in Afghanistan: immediately lift all restrictions on girls’ access to secondary education,” he said.

At the summit, Somaya Faruqi, who was part of the acclaimed robotic team for girls in Afghanistan, said the Taliban are “slowly wiping out our existence in society.”

“Thousands of girls may never go back to school. Many were married. Promises to reopen schools have come and gone,” she said.

Appealing to world leaders, she said, “You must not forget those who are being left behind, those who are not fortunate enough to go to school.”

“Show your solidarity with me and millions of Afghan girls.”

The UN General Assembly – with its epic traffic and demonstrations blocking midtown Manhattan – is back in person after two years of the pandemic, and leaders must appear if they wish to speak.

The General Assembly voted for just one exception — Ukrainian President Volodymyr Zelenskyy, who is leading resistance to a Russian invasion.

Russian Foreign Minister Sergei Lavrov traveled to the summit in New York, where he heard an appeal from his French counterpart Catherine Colonna on Monday to allow a safe zone outside the Zaporizhia nuclear power plant, whose occupation by Moscow is raising concerns.

Also high on the agenda of UN week is Iran, whose uncompromising President Ebrahim Raisi is traveling to the General Assembly for the first time.

In a US television interview ahead of his arrival, Raisi said Iran wanted “guarantees” before returning to a nuclear deal that former President Donald Trump scuttled in 2018.

“We cannot trust the Americans because of the behavior we have already seen from them. So there’s no trust when there’s no guarantee,” he told CBS News’ 60 Minutes.

Biden supports a return to the 2015 deal, under which Iran drastically scaled back its nuclear work in exchange for promises of an easing of sanctions.

But the Biden administration says it’s impossible in the US system to promise what a future president would do.

Colonna said French President Emmanuel Macron could meet Raisi in hopes of progress.

But she warned: “There is no better offer for Iran.”

“It’s up to them to make a decision.”

Raisi can expect to be dogged by protests during his visit, including by exile groups who have called for his arrest over mass executions of opponents a decade after the 1979 Islamic Revolution.