UNITED NATIONS (AP) — The U.N. envoy for Afghanistan urged the Security Council on Friday to demand that the Taliban immediately stop attacking cities in their offensive to take more territory as American and NATO troops pull out of the country.

Deborah Lyons also called on the international community to urge both sides to stop fighting and negotiate to prevent a “catastrophe” in war-torn Afghanistan. The latest Taliban surge, she warned, is reminiscent of attacks on large urban centers in Syria’s war and the Bosnian war in the 1990s that devastated Sarajevo.

For his part, the Afghan ambassador to the United Nations denounced the Taliban offensive as a “deliberate act of barbarism," and claimed the insurgents are being aided in their onslaught by more than 10,000 foreign fighters from 20 terror networks, including al-Qaida and the Islamic State group. He offered no evidence to back up his claim.

“This is not a civil war, but a war of criminalized and terrorist networks, fought on the back of Afghans," said Ambassador Ghulam Isaczai.

Lyons, speaking to an in-person meeting of the council virtually from Kabul, appealed to council members to act with unity to “prevent Afghanistan from descending into a situation of catastrophe so serious that it would have few, if any, parallels this century.”

The Taliban have for months stepped up attacks across Afghanistan, laying siege to provincial capitals in the south and west of the country after capturing district after district and even seizing several key border crossings. As U.S. and NATO forces complete their final pullout from the country by the end of the month, the Taliban have now turned their guns on several provincial capitals.

On Friday, the Taliban appeared to have taken their first provincial capital — the city of Zaranj in southern Nimroz province, though the Afghan government claimed there was still fierce fighting underway and that the city had not fallen.

Isaczai, the Afghan ambassador, stressed that the Taliban are violating the accord they signed with the United States in Qatar’s capital of Doha in February 2020. The deal was meant to allow for American troops to gradually leave Afghanistan after 19 years of war and pave way for intra-Afghan negotiations that would shape the country’s political future.

Under the accord, the Taliban pledged to combat other terror groups — including al-Qaida, which they once harbored — and prevent militants from using Afghan territory to stage attacks on America.

But the link between the Taliban and these foreign militant groups, the ambassador claimed, is “stronger today than at any point in recent times” — with “unprecedented" links to drugs, smuggling and robbing of Afghanistan’s natural resources.

The ambassador appealed on the Security Council “to compel the Taliban to end their campaign of violence and terror against our people and to prevent further bloodshed and urge them to return to talks.”

He also urged the council to impose more sanctions on those involved in the current violence and reiterated Kabul's standing accusation against Islamabad, insisting that the Taliban “continue to enjoy a safe have in and supply and logistic line extended to their war machine from Pakistan.”

Lyons urged participants in meetings next week in Doha, where the Taliban maintain a political office, to convey to the insurgents that “a government imposed by force will not be recognized.”

U.S. deputy ambassador Jeffrey DeLaurentis echoed Lyons, saying that the international community “will not accept a military takeover of Afghanistan or a return of the Taliban’s Islamic Emirate” — and if they choose that path they “will be isolated and an international pariah.”

The Security Council's emergency session followed a statement from earlier this week in which the world body called for a cease-fire and peace talks, and condemned the July 30 attack on the U.N. compound in western Herat province that killed an Afghan security guard.

Whether the council decides to take further action in response to Lyons and Isaczai's appeals remains to be seen.

Lyons said the Taliban’s attempt to seize urban centers has come with “an extremely distressing” human toll: at least 104 civilians killed and 403 wounded in fighting to take Laskhar Gah, the capital of Helmand province since July 28; more than 460 civilian casualties registered in Kandahar since the start of the offensive there on July 9; and credible reports received by the U.N. of over 135 civilian casualties in western Herat province.

The latest fighting comes on top of an increasing humanitarian crisis and severe drought, she added, with 18.5 million people, almost half the country’s population, in need of humanitarian assistance. She urged donors to contribute to the U.N. appeal for Afghanistan, which is only 30% funded.

“Whether the Taliban take additional cities, or whether the government regains districts, the results will only prolong Afghanistan’s agony,” Lyons said, stressing the critical need for a halt to fighting first and then for negotiations. “Otherwise, there may be nothing left to win.”

Edith M. Lederer, The Associated Press