Syria could become a "Mediterranean Afghanistan" if the international community does not act to end its civil war, Turkish president Abdullah Gul warned in an interview published by the Guardian on Sunday.
Gul, who was speaking to the British newspaper during a visit to the Scottish capital Edinburgh, called the world's response "very disappointing" and said the UN Security Council's reaction had been a "disgrace".
He argued that many of the war's casualties could have been avoided if the outside world had reacted strongly to President Bashar al-Assad's crackdown against rebel forces, which he warned were now in danger of becoming radicalised.
Relations between once close allies Damascus and Ankara have deteriorated since the uprising, which began in March 2011.
The president warned he would react "in the strongest way possible" if the conflict spilled over the 900-kilometre (565-mile) border.
"But let me also say that this is not a bilateral issue between Turkey and Syria," he added in comments published on the Guardian's website.
"We did not have any conflict with Syria, but when... there was massacring of the people of Syria, then it became a matter for mankind, for us all."
Some 200,000 refugees are currently living in camps in Turkey, according to Gul.
He went on to say that the "indifference" of the international community was breeding extremism.
"If the atmosphere remains as it is, then this can lead to more radicalisation and some groups in the civil war becoming more extreme," he said.
"I don't think anybody would tolerate the presence of something like Afghanistan on the shores of the Mediterranean.
"For that reason the international community must have a very solid position with respect to Syria."
Gul accused allies of providing insufficient backing for Turkish efforts to negotiate with Assad at the start of the conflict.
"We all worked very hard and at the time we even faced pressure from our allies because they said this was going on too long and it wasn't going anywhere."
If he had been able to pursue talks with Assad, Gul believes that "100,000 people may not have died and Syria would not have faced so much destruction."
He also suggested that Assad had agreed to a Russia-sponsored plan to destroy his chemical weapons stock in order to strengthen his position.
"I think it is very disappointing to see the whole discussion reduced to a discussion solely on chemical weapons," he added.