KABUL, Afghanistan — Fear stalks this city’s market stalls, back alleys and dusty roads — fear that an upcoming agreement between the United States and the Taliban will trigger worsening violence and even a new civil war.

Even as the U.S. and the Taliban head toward the deal that could see American troops withdraw from Afghanistan, few people remember what peace feels like after decades of violence.

“If the USA leaves Afghanistan, the Afghan army is not in a position to stand on its own feet,” Najeeb Hayat, 61, a tailor from Kabul. “Anyone with weapons in Afghanistan will have power, it will be very difficult to stop them and will result in a civil war again.”

The deal would end the United States’ 18-year involvement in Afghanistan — America’s longest war — claiming the lives of some 2,300 U.S. troops. But conflict has raged in Afghanistan for decades.

In 1979, Soviet troops invaded and occupied the country until February 1989. Three years later, the Soviet-backed government of President Najibullah Ahmadzai collapsed and the country descended into a vicious civil war which eventually swept the Taliban to power in 1996.

The militants ruled until the U.S. invasion in 2001, imposing their hard-line interpretation of Islamic law under which women were barred from attending school or holding jobs, and ethnic and religious minorities were brutally oppressed.

Since the United Nations began systematically documenting the impact of the war on Afghan civilians in 2009, it has recorded more than 100,000 civilian casualties, with more than 35,000 killed and 65,000 injured.

The years of conflict and poverty have made Afghans the second largest group of refugees — after Syrians — around the world.

And now it is America’s turn to try and leave.

The U.S.-Taliban deal due to be signed in the Qatari capital of Doha on Saturday is expected to set out a timeline for the withdrawal of American troops. This will come in exchange for the Taliban agreeing to cut ties with terrorist groups — namely Al Qaeda, which the Taliban sheltered before and after the Sept. 11, 2001, terror attacks on the U.S. — and entering into peace talks with their foes in the Afghan government.

While hopeful that the plan will succeed, history has taught many Afghans that foreign troops bring war and, in a seemingly inescapable cycle, their withdrawal can also lead to conflict.

“If the USA doesn’t take careful and deliberate steps in withdrawing their troops from Afghanistan, it will lead to internal and international conflict,” said Dawlat Waziri, a former defense ministry spokesman who was injured as a young officer when Soviet troops stormed the office of the Afghan chief of staff in December 1979.

One fear is that after the U.S. leaves, the Taliban will intensify its offensive against Afghan President Ashraf Ghani, an ally of Washington. The militants, who have made steady military and territorial gains in the last decade, have persistently dismissed Ghani as an American puppet, and it remains unclear whether they are ready to negotiate a genuine peace settlement. Traditionally, the militants have rejected taking part in elections and have called on Afghans to boycott votes.

Two senior Taliban leaders, one in Doha and one in Afghanistan, told NBC News that they would have no choice but to wage war against the Afghan government if the U.S did not fulfill its commitments as part of the deal slated to be signed Saturday.

However, both leaders — who spoke on the condition of anonymity because they are not authorized to speak to the media — cautioned that they were confident this time that the U.S. would honor its commitments.

The Taliban’s senior spokesmen did not respond to a request for comment.

‘Almost too strong’

Analysts cautioned against jumping to conclusions that there would be an immediate escalation of violence after Saturday.

“It’s not as if U.S. forces are guaranteed to leave no matter what happens on the ground in Afghanistan,” Andrew Watkins, a senior analyst at the International Crisis Group think tank, said. “There do seem to be some conditions.”

Earlier this week, Secretary of State Mike Pompeo said the Taliban had to respect the agreement specifically regarding the promises sever ties with terrorists.

“We’re not required to leave unless they can demonstrate they’re fulfilling every element of their end of the bargain,” he said.

Some experts say the future of Afghanistan would really hinge on successful talks between the Taliban and the Afghan government taking place after the signing of the U.S.-Taliban deal.

“One of the worries now is that the Taliban is almost too strong, that the non-Taliban side, the government and everyone else cannot unite,” said Ashley Jackson, a research associate at the London-based Overseas Development Institute think tank.

And many Afghans worry that a U.S. troop departure could open the way to the Taliban regaining power and returning the country to the brutal repression that characterized their rule in the 1990s.

But Jackson said she did not expect the Taliban to immediately march on Kabul, saying overt aggression would risk damaging its relations with the international community.

“I think they would think twice about the political implications of just trying to grab as much territory as they could, unless they were sure they could withstand the political fallout of doing so,” she said.

However, this was not to say, she added, that they would not continue their strategy of “creeping control,” which has allowed them to extend their influence throughout the nation.

Watkins said the Taliban had a lot to lose from reverting back to conflict, highlighting their hope that international aid and trade relations would continue no matter the makeup of a future Afghan government

“The Taliban doesn’t wish to return to the status of a pariah state,” he said.

Still, he cautioned that there were plenty within their ranks who believed they were on the winning side.

While many Afghans remain skeptical of the diplomatic process taking place in Qatar, not everyone believes it is doomed to fail and some draw confidence from the international spotlight on the nation.

“During the Soviet withdrawal, the Afghan national army was in a better situation, but today Afghanistan has more international cooperation,” said Mustafa Aqeli, a Kabul resident with a masters degree in international relations.

It “will not lead to civil war.”

Ahmed Mengli reported from Kabul, Mushtaq Yusufzai from Peshawar, Pakistan, and Saphora Smith from London.