Forty-six Turks held hostage for months by Islamic State jihadists in northern Iraq were freed and returned to Turkey on Saturday, to emotional family reunions and a triumphant Prime Minister Ahmet Davutoglu.

The Turkish diplomats and their children were seized along with special forces officers in their consulate in the city of Mosul on June 11 as IS militants overran whole swathes of northern Iraq.

Davutoglu announced their liberation early Saturday and cut short a visit to Azerbaijan to greet the ex-hostages. He gave no details of the circumstances of their release, though other officials and media reports spoke of a "secret operation".

"Early in the morning our citizens were handed over to us and we brought them back into our country," Davutoglu told reporters before leaving the Azerbaijani capital Baku.

Ankara said three of the consulate's Iraqi staff had been released earlier by the militants.

Turkey's intelligence agency, armed forces and police had worked to secure the hostages' freedom, Davutoglu said after going to meet them in the city of Sanliurfa near the Iraqi border and flying on with them to the Turkish capital Ankara.

"There are unnamed heroes, like those who brought our citizens back to Turkey. They acted for the sake of our country, for the sake of our people. I salute them," the prime minister told a cheering crowd of supporters waving Turkish flags as he stood atop a bus at Ankara's airport.

He kissed one of the freed hostages, consul-general Ozturk Yilmaz, on the forehead, after saying the hostages had "stood strong" and unbowed during their captivity.

Yilmaz said: "I am proud of what I have gone through for my country." He added that he "never lost hope" and was "very happy" to be back in Turkey.

- 'Secret operation' -

President Recep Tayyip Erdogan said the Turkish authorities had carried out a "pre-planned, detailed and secret operation".

"It continued all through the night and was successfully completed in the early morning. From the very first day, our intelligence agency has followed the issue with patience and determination and finally carried out a successful rescue operation."

Although officials gave no details of the operation, private NTV television said Ankara had not paid any ransom and instead had negotiated with local authorities in Iraq.

No other countries were involved in the operation and there were no clashes with the IS militants, NTV said, citing anonymous security sources.

The hostages were taken to eight different locations during their captivity and the spy agency tracked their whereabouts by drones and other equipment.

Turkish Foreign Minister Mevlut Cavusoglu said IS had promised to free the hostages earlier in contacts through mediators, but the promises were not kept.

"The last date they gave was September 20. Therefore we did what was necessary when the time came," he said.

"I hope we will never face such a test in the future. I think our state was very successful in passing this test," he said.

On his Twitter account, he thanked "all those who contributed to the release of the hostages", especially the spy chief Hakan Fidan.

The Islamic State had also kidnapped 31 Turkish truck drivers in early June in Mosul and had released them a month later.

IS militants have seized a swathe of territory in Iraq and Syria, declaring an Islamic "caliphate", committing widespread atrocities and instituting a brutal interpretation of Islamic law. They have recently beheaded three Western hostages, causing an international outcry.

Turkey, a NATO member and Washington's key ally in the region, has been reluctant to take part in combat operations against Islamic State militants, or allow a US-led coalition to use its airbases for strikes against the jihadists, citing its concern over for the safety of its hostages.

Ankara has rejected criticism that it indirectly encouraging the formation of Islamic State through its support of Islamist elements within the Syrian rebellion against President Bashar al-Assad.

Under international pressure, Turkey in June put the Al-Nusra Front -- Al-Qaeda's franchise in Syria -- and the Islamic State extremists on its list of terrorist organisations.