KARACHI, Pakistan — Gunmen killed four aid workers in an ambush in the northwestern Pakistani district of North Waziristan on Monday, police officials said, an attack that could signal a revival of insurgency in the region bordering Afghanistan that was once a stronghold of the Pakistani Taliban.
A vehicle carrying the aid workers, who were all Pakistanis and who were affiliated with a program for developing household skills for women, was fired upon by unidentified attackers in the town of Mir Ali, the police said.
The four aid workers, all women, were killed and the male driver was wounded. A fifth aid worker, also a woman, survived the attack by taking refuge in a nearby house, the police statement said. The attackers fled into the nearby mountains.
The Human Rights Commission of Pakistan condemned the attack and demanded that the government bring the attackers to justice.
“It is the responsibility of the authorities to protect the lives and property of citizens at all costs,” the commission said in a statement.
There was no immediate claim of responsibility for the ambush. But the shooting fits a pattern of attacks against aid workers and anti-polio medics across the country that officials have attributed to the Pakistani Taliban.
Waziristan was the hub of the insurgent group for years, until a strong push by the Pakistani military around 2014 cleared most of the militants, bringing a semblance of security to the region. Analysts and residents now fear that various factions of the Pakistani Taliban who had sought shelter from military operations in the bordering provinces of Afghanistan have regrouped.
Frequent reports of targeted assassinations of tribal elders, roadside bomb attacks, and clashes with security forces have raised fears that the region, which had a tribal status before fully integrating into the rest of Pakistan through legislation in 2018, will relapse into militant control.
Mohsin Dawar, a member of Parliament elected from North Waziristan and a leader of an ethnic Pashtun movement that seeks equal rights, wrote on Twitter, “The wave of indiscriminate killings continues unabated in our region with no end in sight.”
“Where is the State?” he asked.
In a separate attack, five members of the military were killed and another wounded when militants attacked a security checkpoint in South Waziristan late Thursday night, according to the Pakistani military.
The Pakistani Taliban, in a statement, claimed responsibility for that attack, saying that the military unit had been conducting an active operation against the group in the region.
The military also said that two militants and a member of the army were killed during a search operation carried out on Friday night.
Muhammad Amir Rana, director of Pak Institute of Peace Studies, an Islamabad-based research organization, said that the rise in assaults in the former tribal districts was a cause of concern for national security. But, he added, the militants might not be able to regain their old strength because the security forces continue to hunt them actively.
“Reunification of the Pakistani Taliban has been posing a threat in former tribal districts, but now they are not in a position to gain the strength it had before 2014,” Mr. Rana said.
The killing of the four aid workers has also renewed security fears among charity and aid groups working in Pakistan, particularly in the former tribal districts.
An aid worker in the tribal areas, who spoke on condition of anonymity because of a fear of reprisals, said that both the government and the militants viewed him and others who work for aid groups with suspicion since the raid on Osama bin Laden in the Pakistani town of Abbottabad in 2011. The United States intelligence service had reportedly staged a fake vaccination campaign in the area to gather DNA samples to confirm Bin Laden’s presence.
The aid worker said that the recent attack would again force aid organizations to rethink their security measures and decide whether they could continue to work in the former tribal areas.