A Qatari party of 26 hunters kidnapped in southern Iraq in 2015 has been freed and was being handed over to a delegation from Doha in Baghdad on Friday, officials said.

Sources close to the negotiations said their release was part of a far-reaching regional deal involving the freeing of prisoners and the evacuation of civilians in neighbouring Syria .

"The interior ministry has received the Qatari hunters, all 26 of them," the minister's adviser, Wahab al-Taee, told AFP news agency.

The men were handed over to a Qatari delegation and left for Doha, a ministry spokesman said in a statement. An airport official told The Associated Press the group departed on Friday afternoon on a private Qatari jet from Baghdad airport.

The group of hunters, believed to include one or several prominent members of the Qatari royal family, were kidnapped in mid-December 2015 during a hunting trip in the Muthanna governorate of southern Iraq.

They were taken from a desert camp for falcon hunters in southern Iraq in Muthanna province, some 370km southeast of the Iraqi capital.

Little information had surfaced since their abduction as to their whereabouts or condition. In April 2016, the Qatari Foreign Ministry said one of the hunters and an Asian worker on the trip had been freed.

READ MORE: Qatari royal freed by kidnappers in Iraq

Taee would not provide details of the terms of their release but a source close to the negotiations told AFP on condition of anonymity that it was part of a broad regional deal.

"The Qataris are now in [Prime Minister] Haider al-Abadi's office following a deal between Jabhat al-Nusra and the kidnappers," the source said, referring to the former al-Qaeda affiliate now known as Jabhat Fateh al-Sham.

There was never any claim of responsibility for the kidnapping of the hunters, who were seized in a Shia area of Iraq and widely believed to have been nabbed by militias with close ties to Iran .

Hoshyar Zebari, Iraq's former finance minister, wrote on Twitter shortly after the hostages were released that the deal - brokered by Qatar and Iran - violated Iraq's sovereignty.

Release of Qatari hunters in Iraq after 16 months in captivity by a pro Iranian & Hizbulah Shia armed group is a travesty of sovereign Iraq. — Hoshyar Zebari (@HoshyarZebari) April 21, 2017

The deal was linked the evacuation of thousands of people from four besieged towns in Syria: the northern Syrian villages of Fouaa and Kefraya, which are government-controlled but have been besieged by rebels, and the central villages of Madaya and Zabadani, which were besieged by pro-government forces.

Syria deal

The evacuations were under way on Friday, with hundreds of people from two rebel-besieged villages in Idlib being taken to Aleppo, which has been under full government control since late last year.

The evacuees were forced to spend two nights in their buses at a marshalling area after a last-minute disagreement over the release of prisoners held by President Bashar al-Assad 's government.

The evacuations began last week, but were delayed after a car bombing killed 126 people, 68 of them children, at the transit point in Rashidin on April 15.

Assad on Friday blamed Nusra for the bombing in an interview with Russia's RIA Novosti news agency.

The evacuations mark the end of the first stage of a deal brokered by government-allied Iran and Qatar, a longtime supporter of Syrian rebel groups.

The release of the Qatari hunters follows a similar pattern to that in 2015 of 18 Turkish workers, who were freed as part of a deal that also saw the lifting of sieges on Shia villages in northern Syria.

Qatar and Turkey have long had ties with Syria rebel groups.