The Turkish Prime Minister has vowed to hit back after an air strike in Syria that killed three Turkish soldiers.
It represents the first Turkish deaths at the hands of Syrian government forces since Turkey launched a cross-border incursion in August.
Prime Minister Binali Yildirim says it is clear some people are not happy with the battle Turkey has been fighting against the self-proclaimed Islamic State.
"This attack will surely have a retaliation. These attacks, regardless of where they come from, will never affect Turkey's determination in the fight against terrorism."
Direct confrontation between Turkey and Syrian government forces backed by allies including Russia, would mark a serious escalation in an already complicated battlefield in northern Syria.
Mr Yildirim says Europe needs to decide if it wants to shape a future with Turkey.
"They should make a decision. On the one hand Europe says that Turkey is irreplaceable to maintain security in Europe but on the other hand, they take such decisions by making petty excuses. This is a contradiction."
The French President has met his Slovak counterpart, both urging the international community not to stay emotionless about bombings in Syria.
Mr Hollande says the pair discussed key international events, including the war in Syria.
"We have to look straight at what is happening in Syria and especially at this very moment. As I speak to you, one million people are besieged in terrible conditions, with the bombings. We cannot stay emotionless, France is speaking out, France is alerting the international community, France will continue doing so."
The London-based Syrian Observatory of Human Rights says more than 140 civilians have been killed in a week of renewed and fierce bombardment on the rebel-held part of eastern Aleppo.
No aid has reached the area since July, and no civilians have been able to leave.
The head of Syria's White Helmets civil defence group says people in eastern Aleppo are facing starvation and death due to a lack of medical supplies.
The volunteer group has rescued thousands of people from bombed buildings.
But White Helmets Chief Raed Al Saleh says the group is running out of basic equipment from trucks to diesel and gas masks.
"I think that we will start losing people due to starvation and due to a lack of medical emergency materials in less than 10 days."
Rebels in besieged eastern Aleppo have agreed to a UN plan for aid delivery and medical evacuations.
United Nations spokesman Jan Egeland says the UN is now awaiting permission from Russia and the Syrian government.
"The trucks are ready, the humanitarian workers are ready, courageous humanitarian workers will be able to go with hundreds of truck loads of medical equipment, food and all of the other things needed in eastern Aleppo. And we are ready to evacuate hundreds of wounded to medical facilities in both west Aleppo and in opposition-held Idlib. We are ready, we need approval of the parties."
With freezing winter conditions setting in, about 275,000 people are still trapped in east Aleppo.
The last UN food rations were distributed on November 13th.
