‘World will be watching’ Syria ceasefire: Obama warns Russia

US President Barack Obama put the onus for upholding a ceasefire in Syria firmly on the regime and its Russian ally, warning Moscow and Damascus that the "world will be watching." 

Hours before the Saturday cessation of hostilities comes into force, Obama huddled with his top national security advisors on Thursday to plot the way forward and discuss the campaign against the Islamic State group.

"Everybody knows what needs to happen," Obama said, welcoming a partial ceasefire that has ravaged Syria for five years, killing 270,000 people and displacing more than half of the population."All parties that are part of the cessation of activities need to end attacks, including aerial bombardment. Humanitarian aid must be allowed to reach areas under siege."  "A lot of that is going to depend on whether the Syrian regime, Russia, and their allies live up to their commitments," he said in remarks at the State Department.

"The coming days will be critical, and the world will be watching." Many inside Obama's administration -- as well as independent observers -- express grave doubts that even a partial ceasefire can hold. Obama said he was not "under any illusions" about potential pitfalls, but said the ceasefire could be a "potential step in bringing about an end to the chaos".