Turkey on Sunday said it shot down a Syrian fighter jet for a breach of Turkish airspace, as Prime Minister Recep Tayyip Erdogan warned of a "heavy" response to future violations. Syria accused its northern neighbour of "flagrant aggression" after Turkish forces shot down the warplane as it bombarded rebels near the border. But the Turkish military said two Syrian MIG-23 planes approaching its airspace were warned "four times" to turn away and that it scrambled fighter jets when one refused to do so. "Despite the warnings the second Syrian plane entered Turkish airspace at 1313 local time (1113 GMT) .... and breached it by approximately one kilometre and then headed to the west and kept flying 1.5 kilometres inside our airspace," the army said in a statement on its website. "One of the patrolling F-16 jets fired a missile at the Syrian plane at 1314 local time (1114 GMT) in line with rules of engagement and the plane fell into the Kasab region on Syrian territory, 1,200 metres from the border," it added. Both Erdogan and President Abdullah Gul congratulated the Turkish armed forces following the incident. "Our response from now will be heavy if you violate our airspace," Erdogan warned during an election rally, addressing the regime of Syrian President Bashar al-Assad. Parliament speaker Cemil Cicek said Turkey had acted within its rights under international law, media reported. Turkish warplanes last year downed a Syrian helicopter, which Ankara said was detected two kilometres inside Turkish airspace. Turkey toughened its rules of engagement after the downing of one of its fighter jets by the Syrian air force in June 2012, to say that any military approach of the Turkish border from Syria would be considered a threat. A staunch opponent of the regime in Damascus, Turkey hosts more than 750,000 refugees from the three-year Syrian conflict, many of them in camps along the border.