Syrian army jets carried out at least 25 air strikes on the ISIS-held city of Palmyra on Friday, a group monitoring the war said, the second intense bombardment of territory held by the militants in two days. The Syrian Observatory for Human Rights said it was one of the most sustained government bombardments on Palmyra. It came a day after Syrian jets heavily bombed ISIS bastion in the north, the city of Raqqa. Palmyra, in central Syria and home to vast Roman-era ruins, was seized by ISIS insurgents from government forces in May.