One of the six nooses prepared for men sentenced to death at a prison in Kabul. (Massoud Hossaini/AP)

Afghan officials hanged six Taliban prisoners Sunday, a resumption of executions in the war that makes good on President Ashraf Ghani’s recent promise to deal harshly with insurgents, now that hopes for peace negotiations have evaporated.

The inmates were hanged in the morning inside Pul-i-Charki prison — a detention facility on the outskirts of Kabul that was the site of mass executions by the country’s then-communist regime during the 1980s.

Among those hanged were two Taliban members involved in the assassinations of two senior government officials in recent years, officials said.

One prisoner facilitated a 2011 suicide attack on Burhanuddin Rabbani, who served as the country’s temporary president after U.S. forces helped topple the Taliban government 10 years earlier.

The second Taliban member was involved in the 2009 assassination of Abdullah Laghmani, the deputy chief of the Afghan National Directorate of Security.

Ghani administration officials released photos of the six men but did not provide details about the four other prisoners. Pul-i-Charki prison is where Anas Haqqani — son of Jalaluddin Haqqani, founder of the Haqqani network — has been held since 2014. Haqqani, whose family’s network has gained increasing influence within the Taliban, was not among those who Afghan officials said were executed.

The six hanged were found guilty of crimes against “civilian national security,” officials said, adding that Ghani signed the order of execution in response to “repeated demands of the families of victims of terrorist attacks.”

The executions come amid increasing security concerns. Taliban forces have vowed widespread attacks on the heels of a robust spring poppy harvest — a main source of income for the insurgent group through the heroin black market.

Government officials had stopped executing imprisoned insurgents during President Hamid Karzai’s administration, in the hope that the Taliban would enter into peace negotiations.

But in the wake of a suicide bombing in Kabul last month that killed 64 people and wounded about 350, Ghani said he is no longer interested in negotiating with Taliban leaders.

The Taliban responded to the hangings with a cold threat of more violence.

“For taking our revenge on the enemy, we have thousands of equipped suicide bombers,” said Zabiullah Mujahid, the group’s spokesman.

On the day after two Romanian soldiers were killed in an apparent insider attack in the south while training Afghan security forces, news of the hangings drew praise in Kabul.

“Justice and security are tied together,” said Jawed Kohistani, a retired Afghan general who works as a political analyst.

“The Taliban and other terrorists thought in the past that if they are arrested, they can buy their way out by money or other means,” he said. “Now with the executions, they will feel fear in their hearts that they will face justice and cannot be spared.”

Officials with the NATO mission in Afghanistan said they are investigating whether the Taliban is behind the deaths of the Romanian soldiers in Kandahar province.

Army Brig. Gen. Charles H. Cleveland, spokesman for the U.S.-led mission, said the Romanians were assisting with hands-on training “when some of those they were training apparently fired on them.”

Other NATO soldiers killed the two attackers, he said.

“As for what comes next, the details are still to be determined, but at a minimum, we will continue our efforts to partner with the Afghans to provide training, advice and assist efforts,” Cleveland said.

A Kandahar police official said the shooting occurred after an argument erupted between the Romanians and the trainees, before one police officer who has been with the department for several years drew his gun and began firing.

“The cause of the incident is not fully clear,” said Zia Durrani, the police official.