A faction of the Pakistani Taliban said Sunday that it executed 23 paramilitary soldiers who have been held captive since 2010, even as other elements of the militant group continue preliminary peace talks with the country’s government.

In a written statement and subsequent video message, the Pakistani Taliban’s Mohmand wing said that the Pakistani soldiers were killed in retaliation for continued security operations against Islamist extremists. Omar Khalid Khurassani, a commander of the group, also accused Pakistan’s military of extrajudicial killings.

“We have warned the government time and again through the media to stop the killing of our friends, who were in the custody of security forces, but the government continued killing our people,” Khurassani said in the written statement. “So we executed 23 members of the parliamentary” Frontier Corps.

There was no immediate comment Sunday from Pakistan’s government or military, and Khurassani’s statement could be not be independently verified. But the Taliban, which is waging a bloody insurgency aimed at instilling Islamic law in Pakistan, has killed dozens of captured or kidnapped Pakistani soldiers over the years.

In January 2013, the Taliban released video showing the killing of 15 soldiers. A year earlier, the military recovered the bodies of 14 Frontier Corpsmen who had been tortured and shot multiple times after they were kidnapped in 2010.

Khurassani said Sunday that the 23 executed soldiers also had been captured in 2010, as they manned a checkpoint in northwest Pakistan near the Afghan border. They were killed, he claimed, because 16 militants thought to have been in prison had been found dead in various Pakistani cities in recent weeks.

Pakistan’s Frontier Corps largely patrols the country’s restive western border with Afghanistan, allowing the better-trained-and-equipped Pakistani army to remain focused on its historical foe, India, along its eastern border. Over the years, the Frontier Corps has endured heavy casualties as it seeks to contain Taliban insurgents who effectively control many tribal areas of northwest Pakistan.

If confirmed, the most recent killings could be a serious blow to Prime Minister Nawaz Sharif’s effort to reach a negotiated settlement with Taliban militants.

After months of effort, Sharif’s government entered into preliminary talks with Pakistani Taliban representatives three weeks ago. Since then, however, the country’s struggle against terrorism and violence has only deepened.

Last week, the Pakistani Taliban took credit for a suicide bombing that killed a dozen police officers in Karachi, Pakistan’s largest city. And in the northwestern city of Peshawar, local officials have ordered the closure of all cinemas to try to protect residents from near-daily terrorist attacks from Taliban-linked groups.

The statement Sunday from the Taliban’s Mohmand faction, which operates out of the Mohmand district of Pakistan’s tribal areas, seems all but certain to put new pressure on Sharif and Pakistan’s new army chief, Raheel Sharif, to undertake a military operation against Taliban strongholds in northwestern Pakistan.

In early January, after Taliban militants killed 20 Pakistani soldiers in a suicide bombing, it appeared that the start of such an offensive was underway when the Pakistani military bombarded North Waziristan. But a week after those strikes, which killed 40 militants and reportedly drove tens of thousands of residents from their homes, Sharif appeared before parliament to announce that he wanted to give the peace process another chance.

He appointed a three-member delegation to represent the government. The Taliban also authorized a three-member delegation, led by prominent religious clerics, to represent it.

So far, the two sides have been unable to agree to a cease-fire, which Sharif has stressed is needed before more substantiative discussions can begin.

Craig reported from Kabul.