A prominent leader of the Pakistani Taliban's Jamaat-ur-Ahrar (JuA) faction, Ehsanullah Ehsan, has surrendered to security forces, the military said.
The announcement was made on Monday by Asif Ghafoor, Pakistan's military spokesman, at a press briefing in Rawalpindi, near capital Islamabad.
Ghafoor offered no further details on the arrest, including when and where it took place.
"The people, the state and the institutions of Pakistan have made considerable progress in the betterment of the country's security situation," said Ghafoor.
"We have progressed to the point that the people who've been planning attacks on Pakistan's soil from across the border have started to see that the situation has changed.
"In this regard, I would like to share with you that the banned Jamaat-ur-Ahrar and Tehreek e-Taliban [TTP] spokesperon Ehsanullah Ehsan has surrendered himself to security forces."
Al Jazeera could not independently verify the capture, but Ehsan had been conspicuously absent from his prominent role in liaising with journalists since late 2016.
"If a person who is doing the wrong thing feels that they are on the wrong side and that they should come back towards good, then I don't think there can be a bigger success of the state than this," Ghafoor added.
JuA did not immediately offer a comment on the security forces' claim. If true, it would mark the highest-profile surrender by a Pakistani Taliban commander in years.
In recent history, the group has carried out some of the most violent attacks in Pakistan.
In February, more than 130 people were killed in a series of suicide attacks across Pakistan, several of which were claimed by the JuA.
It also claimed responsibility for the 2016 Easter Sunday bombing in Lahore that killed more than 70 people.
In August, the United States added JuA to its list of "specially designated global terrorists".
The JuA was formed in August 2014 as a breakaway faction of the central TTP by the then-commander of its Mohmand district chief Omar Khalid Khorasani and Ehsan, who left his post as a central TTP spokesman.
JuA rejoined the central TTP the following March but is known to operate independently of the central TTP leadership, which is led by Mullah Fazlullah.
Pakistan army launched a countrywide counter-terrorism operation in February and claims to have killed at least 108 suspected fighters and arrested at least 4,510.
In addition, 558 suspected terrorists have surrendered to security forces since the operation was launched, according to Ghafoor.