The Britain-based Syrian Observatory for Human Rights said a suicide bomber struck a bus transporting rebels through the Atmeh border post, one of several crossings Syrian rebels use to bring in rebel and supplies.

A media activist in the province said the blast killed more than 50 people. The activist, said some 300 rebels from various factions are based near Atmeh and bring in weapons through the crossing.

Idlib is dominated by ultraconservative insurgents, including a alliance linked to Al Qaida including former Nusra Front or Fatah Sham , Free Syrian Army and …

Russian and government airstrikes on the Idlib have intensified since rebels launched a campaign from Idlib to break a government siege of Aleppo's opposition districts on July 31.

At least 97 rebel fighters from Idlib have died in combat in Aleppo since July 31, according to London Based Monitoring Group.

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