U.S.-backed fighters pushed ahead in their offensive in northern Syria on Friday, getting closer to a stronghold of the Islamic State group, opposition activists said. Some 20 IS fighters and four from the SDF have been killed in three days of fighting, the Observatory said. U.N. humanitarian chief Stephen O'Brien warned that access to millions of Syrians in need of help is worsening amid the violence. On Wednesday, SDF fighters, aided by U.S.-led airstrikes, launched their offensive on Manbij, which is on a key supply route linking the Turkish border to the city of Raqqa, the extremist group's de facto capital. The fighting comes as the United Nations Security Council announced Friday it will formally ask Syria to allow humanitarian air drops to besieged areas.

Source: ABC News June 03, 2016 10:18 UTC