Turkey warned Damascus Wednesday it would face "consequences" if it sought to avenge the downing of a Syrian military chopper this week, but said it did not believe a border attack was a retaliatory strike.
A car bomb exploded at Syria's rebel-held Bab al-Hawa border crossing into Turkey on Tuesday -- a day after Turkish warplanes shot down a Syrian helicopter which Ankara claimed violated its airspace -- according to a monitoring group.
Turkish Foreign Minister Ahmet Davutoglu said Tuesday's bombing, which wounded at least 12 people, did not appear to be a revenge attack.
"Our security and intelligence units have been working on this but one should not reach an early conclusion that it was a retaliation," Davutoglu told a press conference in Ankara.
"Such a retaliation against us within Syrian territory cannot be considered," he said, warning: "The Syrian regime should know that it will face the consequences even if it thinks of a retaliation."
Turkey changed its rules of engagement towards Damascus after the Syrian air force downed one of its fighter jets in June 2012.
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The government warned that any military approach of the Turkish border from Syria would be considered a threat.
The US Ambassador to Turkey Francis Ricciardone said Ankara had exercised its right to "self-defence."
"The Turkish government was very clear and transparent, announcing its rules of engagement over a year ago, giving repeated warnings over challenges on Turkish airspace," the ambassador said.
"Turkey acted within its announced intentions," he added, calling the move a "legitimate action of self-defence."
Relations between once close allies Damascus and Ankara have deteriorated since the outbreak of the deadly conflict in Syria in March 2011.
Turkey has lobbied for the ouster of President Bashar al-Assad and provided shelter for Syrian rebels seeking to overthrow him.
The long and volatile border between the two countries has become increasingly tense, with a number of incidents in the area, which prompted NATO to station Patriot missile batteries there for defensive purposes.