UN Secretary-General Antonio Guterres on Monday slammed the Taliban's "broken" promises to Afghan women and girls, and urged the world to donate more money to Afghanistan to head off its economic collapse.

The comments came on the heels of the first face-to-face talks between the United States and the Taliban since the Islamists took control of the country, at which the issue of women's rights was raised, according to the State Department.

"I am particularly alarmed to see promises made to Afghan women and girls by the Taliban being broken," Guterres told reporters. 

"I strongly appeal to the Taliban to keep their promises to women and girls and fulfill their obligations under international human rights and humanitarian law."

Guterres said the United Nations "will not give up" on the issue and said the body discusses it daily with the Taliban, who have been in power since mid-August but whose legitimacy as a government is still not internationally recognized.

"Broken promises lead to broken dreams for the women and girls of Afghanistan," Guterres said, noting that three million girls have enrolled in school since 2001, and the average amount of education for girls has increased from six years to 10.

"Eighty percent of Afghanistan's economy is informal, with a preponderant role of women. Without them, there is no way the Afghan economy and society will recover," the UN chief warned.

Guterres also spoke at length about the challenges faced by Afghanistan's economy. The country's assets held abroad have been frozen, and development aid has been suspended. 

"We need to find ways to make the economy breathe again. This can be done without violating international laws or compromising principles," he said.

"I urge the world to take action and inject liquidity into the Afghan economy to avoid collapse."

According to UN officials, it is possible for international funds or money from blocked Afghan assets to be paid to UN agencies and nongovernmental organizations that then pay salaries to Afghans on the ground.

This practice, with bank exemptions authorized by the United States in particular, has already been used in the past for other countries including Yemen.

But Guterres warned the international community was moving too slowly to give aid to Afghanistan, where the humanitarian and economic crisis affect at least 18 million people -- about half the population.

International humanitarian aid has thus far been delivered to different parts of the country without obstruction from the Taliban, and even with their cooperation and security assistance, he said.

"The number of incidents during humanitarian operations has been in constant decline," Guterres said.