ISTANBUL // Turkish authorities say they have evidence that Kurdish militants enjoying increasingly free rein in Syria brought 40 kilograms of plastic explosives across the border into Turkey to stage a major attack last week.
The claim is a new sign of tension between the two countries that could trigger a military escalation at the border, analysts said yesterday.
"Tensions will rise further, and even an armed confrontation is possible," Ihsan Bal, an anti-terrorism expert at the International Strategic Research Organisation (Usak), a think tank in Ankara, said yesterday.
According to officials quoted by Turkish media, two Kurdish militants who crossed from Syria into Turkey carrying plastic explosives were travelling through Anatolia in a car they collected from accomplices in Turkey last Friday. They panicked when they realised they were being followed by police after driving through a checkpoint in the south-east province of Kahramanmaras.
The militants triggered the explosives after entering a police compound in the town of Pinarbasi, in the province of Kayseri, and coming under fire by police there. The two Kurds and a policeman died, while another 17 people were wounded.
Recep Tayyip Erdogan, Turkey's prime minister, said the militants were probably on their way to stage a major attack in a metropolitan area.
"Had the military police not followed and stopped that car, there might have been a much bigger disaster in one of our big cities," Mr Erdogan said in a Twitter message.
The outlawed Kurdistan Workers' Party (PKK) - a rebel group fighting for Kurdish self-rule in Turkey since 1984 and labelled a terrorist organisation by Turkey and the West - confirmed that two of its members were in the car that exploded.
A PKK statement quoted by the ANF news agency, which is close to the rebels, said the militants had died "a heroic death".
Sinan Ulgen, the chairman of Economics and Foreign Policy Research (Edam), an Istanbul-based think tank, said Turkey was likely to boost its troops on the border.
"Turkey will need to give a strong signal to Syria that this is unacceptable," he said about the reported infiltration by Kurdish militants from Syria.
Mr Ulgen said he did not expect military clashes between the two countries, but added that troop reinforcements were possible because Ankara needs "to appease public opinion and go beyond the war of words" with Syria. Turkey is increasingly concerned that the violence in Syria is destabilising the region along the joint border, which stretches 900 kilometres from the Mediterranean to Iraq.
Last month, Ankara accused Syrian troops of firing across the border at a camp for Syrian refugees.
After the shooting, Mr Erdogan raised the possibility of asking Nato to step in under a rule of the alliance that calls on action by all 28 countries of the bloc in case of an attack against one of its members.
During a decade of warm Turkish-Syrian relations that ended last year, Damascus was careful not to allow the PKK to stage attacks in Turkey from Syria.
But the Turkish government says the crisis in relations following Ankara's outspoken criticism of the Syrian government's clampdown may have prompted Damascus to change its position and allow the PKK to operate in Syria.
Shortly before the incident in Pinarbasi, Idris Naim Sahin, Turkey's interior minister, used a television interview to accuse the Syrian government of supporting the PKK to harm Turkey.
"In an effort to take revenge on Turkey, they close their eyes to the terrorist organisation moving into northern parts [of Syria] and taking over several villages there," Mr Sahin said about the Syrian authorities.
Syria has not commented on the accusation that the regime is tolerating the PKK.
A day after the explosion, Mr Sahin said four people had been arrested for helping the bombers.
"Their connections, including cross-border connections, have been uncovered by police," he said.
According to Turkish media reports, two of the arrests were made in Suruc, a town near the Syrian border. The four arrested men are accused of having met the bombers after they crossed the border from Syria late last Thursday and of having supplied them with the car, according to the reports.
Speaking about a possible troop increase at the border, Mr Ulgen said Turkey had used the method of a military build-up before.
In 1998, Ankara sent tanks to the border with Syria to pressure Damascus to throw out the PKK leader, Abdullah Ocalan, who was living in the Syrian capital at the time.
Following the Turkish move, Ocalan had to leave Syria and was arrested by Turkey several months later. He has been serving a life sentence in a Turkish prison since 1999.