ANKARA (AFP) - Turkish Prime Minister Recep Tayyip Erdogan on Sunday congratulated the military for downing a Syrian warplane near its border and warned of a "heavy" response if its airspace was violated.

"Our response from now will be heavy if you violate our airspace," Mr Erdogan said during an election rally, referring to the regime of President Bashar al-Assad.

"I congratulate the chief of general staff, the armed forces and those honourable pilots... I congratulate our air forces," said the premier.

Syria on Sunday accused its northern neighbour of "flagrant aggression" after Turkish forces shot down the warplane as it bombarded rebels near the border.

Turkish media reported that the army warned two Syrian jets approaching the border to turn away, but scrambled its F-16 jets when one refused to abide by the warning.

The Syrian Observatory for Human Rights said the plane was striking the northern province of Latakia when it was hit, catching fire and crashing in Syrian territory.

Turkish warplanes last year downed a Syrian helicopter, which Ankara said was detected 2km 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.