Syrian forces have carried out air strikes to push back what is being described as a major offensive by militants affiliated with the al-Qaida to seize the key northern city.
The Syrian Observatory for Human Rights reports that rebels fired artillery and hundreds of rockets into seven government-held areas around Aleppo.
Reuters says that the attack that began on Thursday is "the most intense insurgent offensive in Aleppo in three years, [aiming] to build on recent advances against [Syrian President Bashar] Assad by an array of groups fighting on separate fronts, including Islamic State and rebels backed by his regional foes."
But, according to the BBC, "the Syrian state news agency Sana said the assault had been repelled and more than 100 'terrorists' killed.
The BBC's Jim Muir, reporting from Beirut, says that on Thursday, 13 Islamist groups joined al-Nusra Front, al-Qaida's affiliate in Syria, in the coordinated attack.
Reuters quotes a military source as saying that the rebels "had bombarded government-held parts of Aleppo with weapons including highly destructive 'hell cannons' — improvised mortar bombs made out of cooking gas cylinders.
"In addition to most of Idlib province, Assad has also recently lost the central city of Palmyra to Islamic State, and areas of southern Syria to an alliance of rebels known as the 'Southern Front' that profess a moderate vision for Syria."
http://www.npr.org/sections/thetwo-way/2015/07/03/419753903/syrian-forces-try-to-halt-rebel-offensive-on-aleppo
