The U.N. special envoy for Afghanistan on Friday questioned the Taliban’s commitment to a political settlement, telling the U.N. Security Council the war has entered a “deadlier and more destructive phase” with more than 1,000 civilians killed in the past month during a Taliban offensive.

“A party that was genuinely committed to a negotiated settlement would not risk so many civilian casualties, because it would understand that the process of reconciliation will be more challenging, the more blood is shed,” Deborah Lyons said.

The Taliban have stepped up their campaign to defeat the U.S.-backed government since April as foreign forces complete their withdrawal after 20 years of war. The Taliban captured an Afghan provincial capital and assassinated the government’s top media officer in Kabul on Friday.

“This is now a different kind of war, reminiscent of Syria, recently, or Sarajevo, in the not-so-distant past,” Lyons said.

“To attack urban areas is to knowingly inflict enormous harm and cause massive civilian casualties. Nonetheless, the threatening of large urban areas appears to be a strategic decision by the Taliban, who have accepted the likely carnage that will ensue,” she said.

Peace talks between the Afghan government and Taliban negotiators started last year in the Qatari capital of Doha, but have not made any substantive progress.

Russia’s U.N. Ambassador Vassily Nebenzia told the council that the deteriorating situation in Afghanistan was of increasing concern and “with the withdrawal of foreign forces, the outlook looks grim.

“It is clear that there is no military solution to the Afghan situation, but in the current situation – given the absence of progress on the negotiation track – the prospects of Afghanistan slipping into full scale and protracted civil war, unfortunately, is a stark reality,” he said.

Senior U.S. diplomat Jeffrey DeLaurentis urged the Taliban to halt their offensive, pursue a political settlement and protect Afghanistan‘s infrastructure and people.

“The Taliban must hear from the international community that we will not accept a military takeover of Afghanistan or a return of the Taliban’s Islamic Emirate,” he said.

Afghanistan‘s U.N. Ambassador Ghulam Isaczai urged the Security Council to act to “prevent a catastrophic situation.”

“We’re alarmed by reports and incidents of gross human rights violation by the Taliban and their foreign terrorist associates in almost half of our country and we are extremely concerned about the safety and security of people in cities under Taliban attacks,” he said.