In Syria, a bus carrying Turkish pilgrims came under attack near the flashpoint central city of Homs.
At least two people were injured, including the bus driver, the BBC reported, adding that the passengers were understood to have been returning from the Hajj - the annual Muslim pilgrimage to Mecca, in Saudi Arabia.
More on GlobalPost: Bashar al-Assad - "Syria will not bow down"
The private CNN-Turk television station said the bus was attacked by "Syrian soldiers" after taking a wrong turn.
Other reports said the bus was in a convoy of about eight or nine buses, and that a second vehicle had also come under attack.
A Turkish foreign ministry official confirmed to Agence France Press that “an attack took place in Syria,” without offering further information.
He reiterated Turkey's warning that its citizens should not visit Syria.
The incident comes as at least four more people were reportedly killed Monday in afresh violence.
Turkish Prime Minister Recep Tayyip Erdogan has become increasingly vocal in his criticism of the repression of protesters in Syria by the regime of President Bashar al-Assad.
The foreign ministers of the Arab League plan to crisis talks over Syria in Cairo on Thursday.