Syrian and Russian jets are stepping up strikes on opposition forces in northern Syria in retaliation for the sudden offensive that has cost the regime control of the country’s second largest city, Aleppo.

AMMAN, Dec 2 (Reuters) - At least 25 people were killed in northwestern Syria in air strikes carried out by the Syrian government and Russia, the Syrian opposition-run rescue service known as the White Helmets said early on Monday.

NBC News’ Matt Bradley reports on the intensifying violence in the Syrian rebel offensive after Russian and Syrian jets struck a rebel held city in the northern part of the country. Syrian President Bashar Assad is vowed to crush insurgents waging a shock offensive against his regime.