President Bashar al-Assad

About 1,000 Syrians, including a defecting brigadier-general, have fled to Turkey in the past 24 hours to escape intensifying violence, a Turkish official said on Friday.

The latest group brought the number of Syrian refugees in Turkey to 45,500, up from 44,000 at the end of July, said the official, who asked not to be named. At least 25 military generals are among those who have taken refuge in Turkey.

A Syrian activist who monitors refugee flows at the border said 900 people from the towns of Aleppo and Idlib in Syria had arrived since Thursday, citing Turkish border guards, reports Reuters.

Of those, 20 civilians, including women and children, were wounded when their bus came under attack by government forces, said the activist, who declined to be named. They were being treated at Turkish hospitals, he said.

Turkish officials are concerned about a possible flood of refugees from Syria's biggest city Aleppo as President Bashar al-Assad's forces use warplanes and artillery to pound rebel fighters there.

The 17-month uprising against Assad's rule in Syria has created a refugee crisis in Turkey and other neighboring countries. Opposition sources say at least 18,000 people have been killed since the revolt began in March 2011.