Syria's foreign ministry said Wednesday it was skeptical about Turkish efforts to fight the Islamic State (ISIS) group, in its first official reaction since Ankara began airstrikes against the jihadists, AFP reports.
"It is better late than never, but are Turkish intentions to fight the terrorists of Daesh (ISIS), Al-Nusra Front, and Al-Qaeda-linked groups genuine?" the ministry asked in a letter to the United Nations.
"Or is it aiming to hit the Kurds in Syria and Iraq, maybe for other internal reasons?"
Turkey has conducted airstrikes in Syria against ISIS since early Friday, after Ankara claimed a Turkish soldier was killed in cross-border fire by the jihadists.
The raids have also struck Kurdish militants in Iraq, with experts predicting that Turkish President Recep Tayyip Erdogan is using the campaign as a pretext to fight the Kurds - particularly after his party lost badly in elections to a pro-Kurdish party.
The ministry's letter made no direct mention of the strikes, but said that Syria "rejects the Turkish regime's attempt to paint itself as a victim that is defending itself", accusing Ankara of supporting "terrorist" groups.
Turkey also gave formal approval Wednesday for the United States to use a southern air base for raids against ISIS in Syria, after domestic and international criticism that it was not doing enough to curb IS activity along the border.
Syria's regime has repeatedly accused the Turkish government of supporting "terrorists" -- the word it uses to describe all armed groups opposed to Damascus.
"Syria has said for years that terrorism has no nation, religion or borders and warned terrorism's supporters that it would come back to them," the letter read, according to AFP.
"Unfortunately, we have lately begun to witness terrorism beginning to bounce back towards its supporters," it said.
The letter came several days after the British Guardian newspaper reported that evidence was found when U.S. special forces killed ISIS leader Abu Sayyaf in May, revealing that Turkey has in fact been collaborating with the brutal jihadists.
According to that report, when Abu Sayyaf's compound was raided in eastern Syria, it was discovered that Turkey is the main buyer of smuggled ISIS oil which was managed by Abu Sayyaf to economically prop up the terror group.
The report quoted a senior Western official, who told the Observer that the findings at the compound showed direct deals between Turkish officials and ISIS leaders is "undeniable."