UPDATE: 15:02 p.m. IST --  Russia has suspended airstrikes in Syria 'green zone' as part of the ceasefire plan, the Russian defence ministry reportedly said. 

UPDATE: 14:18 p.m. IST -- In a reported breach of the ceasefire that came into effect in Syria Friday midnight, Syrian rebels said they were attacked by regime ground forces Saturday, Reuters reports. Three rebel fighters were reportedly killed. 

Original Story: 

The ceasefire in Syria worked out by the United States and Russia and agreed to by Syrian President Bashar al-Assad and nearly a 100 fighting groups came into effect Friday midnight, making it the first major truce in the nation ravaged by a five-year civil war. The ceasefire is expected to last for two weeks. 

The United Nations Security Council put its weight behind the US-Russia resolution Friday, while US President Barack Obama warned Moscow that "the world will be watching." Russian airstrikes had continued to bombard rebel strongholds in Syria hours before the ceasefire was to begin, while regime bombs killed a woman and a child in the city of Duma Friday, according to monitoring group Syrian Observatory for Human Rights. 

Airstrikes will continue to target the Islamic State group as well as the al Qaeda-affiliated Nusra Front. 

The peace talks that had hit a wall earlier this month will resume March 7, UN  envoy Staffan de Mistura said, according to AFP.

"No shortage of attempts to undermine this process"

Mistura reportedly told the Security Council that all sides should deal with any possible breaches to the ceasefire in a "proportionate" manner, The Guardian reports. 

"No doubt there will be no shortage of attempts to undermine this process...nothing is impossible, especially at this moment," The Syrian peace envoy said. He added that a military response to breaches should be a "last resort."

White House spokesman Josh Earnest also reportedly warned of violations to the Syrian ceasefire deal. 

"We do anticipate we're going to encounter some speed bumps along the way. There will be violations," he said.