Thirty-two Turkish truck drivers held hostage by Islamic militants in Iraq flew back home to Turkey on Thursday following their release after three weeks in captivity, local officials said.

A Turkish plane carrying the truck drivers from the northern Iraqi city of Arbil landed in Turkey's southeastern province of Sanliurfa near the Syrian border late on Thursday.

But a separate group of almost 50 Turks seized in an attack on the Turkish consulate in Mosul last month remain in captivity.

"We were not subjected to ill treatment but we had lived with the fear of uncertainty and death for 23 days," Okkes Sen, one of the truck drivers, told Turkish television.

Another driver, Halil Adam, said militants seized the captives' trucks before they were released around noon and delivered to Turkish consulate staff.

Local governor Izzettin Kucuk told local media that all those released were in a good condition.

Foreign Minister Ahmet Davutoglu had confirmed earlier that the abducted Turks were released and on their way back to Turkey through northern Iraq.

"The 32 drivers were delivered to our consul," Davutoglu said in Ankara.

Previous reports had said 31 truck drivers had been held. They were kidnapped by militants from the jihadist group the Islamic State of Iraq and the Levant (ISIL), who now control swathes of the country.

Davutoglu said that the foreign ministry had been informed of the impending release by the Turkish intelligence agency on Wednesday night but had not made any advanced announcement for security reasons.

He said he had spoken with one of the drivers on Thursday and said that they were unharmed but one of them may need medical treatment.

A government official told AFP one of the drivers, suffering from heart problems, had been carried to Arbil in an ambulance.

Turkish television channels aired pictures of the drivers on a bus, looking relaxed and smiling before their eventual arrival.

- 'Working day and night' -

Militants storming the Turkish consulate in Mosul had also kidnapped 49 other Turks, including the consul, staff members, guards and three children.

There was however no information regarding their whereabouts.

"We will continue to work day and night to bring back the remaining citizens," said Davutoglu.

The official said negotiations were continuing with different groups in Iraq, including tribes, for the release of Turkey's abducted citizens.

The kidnappings sparked intense concern in Ankara over the rise of radical Islamist groups across the border in Syria and Iraq.

Turkey, which backs the uprising against Syrian President Bashar al-Assad, has repeatedly denied accusations that it is itself to blame for the rise of the Islamist rebellion in Syria and Iraq.

Turkey blacklisted ISIL as a terrorist organisation in 2013.

The government of Prime Minister Recep Tayyip Erdogan has also come under fire for its failure to grasp the severity of the radical Islamist threat across the border and evacuate the Mosul compound before the consulate was stormed.

Turkey said it evacuated its consulate in the southern Iraqi city of Basra a week after militants attacked its mission in Mosul.

The government has so far favoured diplomacy over force in response to the kidnapping.

A Turkish court last month imposed a controversial blackout on media coverage of the kidnapping of the Turks, after Erdogan said the reports were "risking the lives of our people".

The government has faced a backlash from opposition parties accusing it of using the release as a propoganda tool in the run up to presidential elections in August in which the prime minister is a clear favourite.