* Hostages seized as insurgents overran Mosul
* Turkey calls on all its citizens to leave Iraq
* New mandate for military operation not on table
* Newspaper says police warn of attack in Turkey (Adds foreign minister)
By Tulay Karadeniz
ANKARA, June 12 (Reuters) - Turkey is negotiating for the release of 80 of its citizens held by Islamist militants in northern Iraq and has confirmed they are unharmed, Turkish Foreign Minister Ahmet Davutoglu said on Thursday.
Sunni insurgents from the Islamic State in Iraq and the Levant (ISIL), an al Qaeda splinter group, seized the Turks, who include special forces soldiers, diplomats and children, in the city of Mosul over the past two days.
They took 49 of the group, including Turkey's consul-general, from the Turkish consulate on Wednesday. They are separately holding 31 Turkish truck drivers abducted a day earlier while delivering diesel.
"This is a very delicate process and we have a very critical and dynamic phase ahead of us," Davutoglu said in a statement to the media, declining to take questions.
"Compared to yesterday they are in a safer position ... We are doing our best to get positive news as soon as possible," he said. The hostages had not been harmed, he said.
The Foreign Ministry warned Turkish citizens against all travel to Iraq and called on those already there to leave, advising them on routes out of the country.
Turkey has close trade and political links with the Kurdish-controlled area to the north of Mosul. That region has not, for the moment at least, been targeted by ISIL. Turkish businesses are also active in other parts of northern Iraq.
The pro-government Turkish newspaper Yeni Safak reported earlier that the hostages had been released to the Iraqi governor of Mosul and would be brought to Turkey on Thursday.
Cetin Nuhoglu, the chairman of Turkey's International Transport Association, told Reuters that the 31 truck drivers had been freed but were apparently trapped at the site because of poor security in Mosul following its capture by the militants.
"There are reports in the media about our citizens being released but we can't confirm these reports at this stage," a Turkish official said. "We have been holding negotiations since yesterday to secure our citizens and these negotiations are still ongoing."
Earlier on Thursday, Justice Minister Bekir Bozdag said the Turkish government was not working on any new mandate to authorise a cross-border military operation into Iraq following the seizure of the 80 Turks.
A parliamentary mandate allowing Turkey to conduct cross-border military operations in Iraq expires in October. It was drafted to enable Ankara to strike at bases of Kurdish PKK militants sheltering in the north of Iraq.
Diplomats and security experts have warned of the risk of attacks by ISIL on Turkish soil.
The newspaper Vatan reported on Wednesday that the national police headquarters in Ankara had issued an internal alert about a possible attack by an ISIL militant who had entered Turkey, ordering forces to intensify security in crowded areas including shopping centres and squares, and around Western embassies.
The national police headquarters in Ankara had no immediate comment. (Additional reporting by Orhan Coskun in Ankara and Ceyda Caglayan, Humeyra Pamuk and Seda Sezer in Istanbul; Writing by Nick Tattersall; Editing by Larry King)