BBC reporter Dilawar Khan Wazir has been released by his captors, a day after being kidnapped in Pakistan.
Mr Khan is not sure who his kidnappers were
Mr Khan turned up shaken but unharmed in the BBC office in the capital, Islamabad, on Tuesday evening.
He had been blindfolded and questioned about his reporting and sources. He did not know who his kidnappers were.
His disappearance prompted the BBC to write to the Pakistan government, which said it could not confirm whether he was in their custody.
Mr Khan is one of the few local journalists reporting on the Pakistani army's fight with pro-Taleban militants in the troubled Waziristan region on the Afghan border.
A number of journalists have gone missing, and some have been killed, after covering stories considered sensitive by the military or the militants.
Media rights watchdog Reporters without Borders welcomed Mr Khan's release.
"It is vital that the authorities now find out who was responsible for this kidnapping, all the more so since it appears linked to his work as a journalist," the group said in a statement.
Police opened a criminal case against "unknown kidnappers" following Mr Khan's disappearance.
The BBC Urdu service reporter said he was seized on Monday afternoon on the outskirts of Islamabad as he was on his way to his home in the town of Dera Ismail Khan in North-West Frontier Province (NWFP).
Six or seven men snatched him from his taxi, bundled him into another vehicle and blindfolded him. He does not know where he was taken.
"Unknown people took me from the taxi, blindfolded me, slapped and kicked me, and then took me to an unknown place. They kept me in a dark room and kept my blindfolds on," the reporter said.
"They were asking different questions... how did I come here, what kind of reporting I do?"
Mr Khan was held for more than 24 hours and then left in a quiet wooded area outside Islamabad on Tuesday evening. He made his way by taxi to the BBC office, about a 25-minute drive away.
Earlier on Tuesday, BBC World Service Director Nigel Chapman had called on the Pakistani government to help locate Mr Khan.
"I am seriously concerned about the whereabouts of our reporter and would request your kind help in tracing him at the earliest," he wrote in a letter to the Pakistani interior ministry.
Interior Minister Aftab Ahmed Sherpao told the BBC: "We are looking into the case and so far we are unable to find him.
"I am not in a position to confirm whether or not he is in government custody."
Mr Khan had been in the capital visiting his brother, Zulfiqar Ali.
Fears were raised on Monday when his mobile phone was answered by someone saying he was seriously hurt in hospital. There was no sign of him when the BBC checked.
Pakistan's record on press safety is poor and Mr Khan has received threats in the past.
In August his 15-year-old brother, Taimur, was killed, although it is not confirmed that the attack was linked to Mr Khan's work.
The journalist and his family have been targeted on a number of other occasions - it is not clear by whom. The family say they have no personal or tribal enemies.
In February 2005 two journalists in the same car as Mr Khan were killed when shots were fired at their vehicle in the town of Wana in South Waziristan. He was unhurt.
They had been reporting on the signing of a peace agreement between the authorities and tribal fighters.
Mr Khan left his home in Wana last year and moved to Dera Ismail Khan after receiving threats from the militants.