For most of Abdul Manan’s life, the border dividing Afghanistan and Pakistan was little more than a line on a map. Like generations of men before him, Mr. Manan, 55, commuted every day from his mud-brick home on the Pakistan side to the wheat field his family had cultivated for decades in Afghanistan. His four sons crossed the border with him, transporting electronics and groceries from markets on one side to homes on the other.

It was a journey shared by tens of thousands of residents in the Pakistani town of Chaman, the site of the last official border crossing where people could pass through using only their national identity card from Pakistan. Then, in October, the gates slammed shut.

Pakistani officials say the restrictions are a necessary security measure — though most of the travel originates on their side of the border — as the country has grappled with a resurgence of cross-border militant violence since the Taliban seized power in Afghanistan in 2021.

For the first time since the border was drawn over a century ago, the Pakistani authorities are requiring residents to show a passport and visa before crossing — paperwork that virtually none of them have, they say.

The rules have upended their daily lives. Small traders say they have been effectively locked out of their shops, where their goods rot and bills for shuttered stores mount. Farmers have missed out on wheat harvests, leaving them unable to feed their families, they say. Porters, who once earned up to $3.50 a day by transporting goods like electrical items and groceries on their backs or on hand trolleys, have lost their only source of income.

In recent weeks, Chaman has erupted in violent protests as residents demand that the restrictions be lifted. “Everything has been taken from us. The land is now inaccessible,” Mr. Manan, 55, said. “We are starving.”

Mr. Manan is one of thousands who have gathered every morning since late October at a makeshift protest camp two miles from the border crossing. Throughout the day, the demonstration’s leaders shout speeches to the crowds, which roar with applause. They break only briefly for midday prayers before gathering again until sunset.

The tensions boiled over in mid-June, after security forces were called in to clear protesters who had blocked the main highway linking Chaman to Quetta, the provincial capital 75 miles away. The officers clashed with the protesters, leaving more than 40 people injured.

In the days that followed, the two sides tried to negotiate but government forces arrested protest leaders, generating accusations that the authorities had invited them for talks as a trap. Pakistani officials say that the arrests were necessary after attacks on paramilitary forces and attempts to seize government buildings.

Negotiations resumed last week and, on Sunday, the government released protest leaders in exchange for a temporary end to the daily protests at the border.

Negotiators also announced that the government would once again allow local tribesmen to cross the border with only a national identity card. But Pakistani officials have not issued an official statement on the issue and many observers are skeptical as to whether they will in fact restore the old system.

For generations, Pashtun tribes living along the rugged frontier traversed the area freely, their lives woven together by shared ancestry and culture, as well as economic dependence.

In 1893, British colonial officials established the Durand Line, a 1,600-mile border dividing Afghanistan and British India. Border tribes continued to cross freely, a tradition that persisted even after the creation of Pakistan in 1947. Extended families lived on either side of the line, crossing to dance at weddings or offer condolences at funerals.

“The only real sign that you had crossed into Afghanistan was the sudden switch in driving sides — from the left in Pakistan to the right in Afghanistan,” said Abdul Rauf, 42, a trader who runs his family’s plastic supply business across the border in Afghanistan.

Pakistani officials first introduced restrictions on the border crossing after the U.S. military invaded Afghanistan in 2001. American forces were concerned about the movements of Taliban fighters.

Two years later, the Pakistani authorities built the so-called Friendship Gate in Chaman, a large concrete gateway along the main highway connecting Chaman to Spin Boldak, the nearest town in Afghanistan.

As the years passed, the constraints tightened further. Border crossings were restricted to 8 a.m. to 5 p.m. each day. Pakistanis from Chaman, in Balochistan Province, and Afghans living in Kandahar Province over the border were required to show their national identity cards to cross. Porters — an essential work force of around 15,000 people — needed special paperwork issued by Pakistan’s border security officials.

And in 2017, a larger border fence was constructed, limiting movement through the dozens of informal crossings along the border. People living close to the fence either relocated or obtained a security pass to travel from one side of their village to the other.

Pakistani officials said that the most recent border restrictions were necessary to prevent militants from the Pakistani Taliban, also known as Tehrik-i-Taliban Pakistan, or T.T.P., from infiltrating Pakistan from Afghan soil.

Since the Taliban takeover in Afghanistan three years ago, violence by the T.T.P. and other militant groups has surged in Pakistan, stoking tensions between the two countries. The Pakistani authorities have accused the Afghan Taliban of providing safe haven to Pakistani militants, a claim that Taliban officials deny.

“These measures aim to strengthen border management and prevent terrorists from entering the country from Afghanistan,” said Shahid Rind, a provincial government spokesman.

But tribes complain that the restrictions have also decimated their livelihoods and, if they remain in place, will forever reshape the fabric of communities.

Mr. Rauf, the trader, said he has not been able to visit his shops across the border for the past several months. “The plastic merchandise I stored outdoors is ruined, and the bills for closed shops — electricity, security — keep piling up,” said Mr. Rauf, who estimated losses exceeding $1,180.

Beyond trade, family ties that span the border have been strained, as people cannot visit graveyards, attend weddings and share in celebrations.

Activities that are “an obligation in Pashtun society” have become “impossible,” said Iftikhar Noorzai, 23, a porter. He said that he had not seen his two sisters, who are married to men in Kandahar, during two Eid festivals.

Even though the Pakistani government promises to help with passport applications, the greatest challenge for most Chaman residents is proving their Pakistani citizenship. The authorities require documents dating back to the 1970s, which many cannot provide.

Human rights groups have urged the government to find a way to balance national security needs and the rights of residents to maintain their livelihoods.

The Human Rights Commission of Pakistan, an independent watchdog, urged “immediate engagement with the affected communities, all stakeholders and Afghan representatives through dialogue and diplomacy” to resolve the issue.

At the protest camp in Chaman, families are exhausted and worried. “Will I ever get back to my land? What will become of my sons if the border stays closed?” said Mr. Manan, the farmer. “We can only pray for a solution that shows mercy on the poor like us.”