US-Russia Brokered Syria Cease-Fire Begins

— -- The Syrian army announced today that it has begun implementing the new, nationwide cease-fire brokered by United States and Russia, which calls on U.S.-backed rebels and Russian-backed regime forces to cease all hostilities. The cease-fire went into effect at sundown in Syria, which occurred at around 12 noon ET.

Parameters for the cessation of hostilities, announced Friday by Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov, call on President Bashar al-Assad's forces to cease all combat air missions targeting rebel forces. It also maps out which groups are considered extremist forces subject to airstrikes from either the regime, Russia, or the U.S. military -- and which are not.

Russia had long complained that U.S.-backed rebels forces are aligned with the Nusra Front, an al-Qaeda linked group. Likewise, the the U.S. has called on Russia to stop striking U.S.-backed oppositions forces.

Nevertheless, the new plan calls for an unlikely military alliance between Russia and the United States. If the cease-fire holds, they've agreed to share military intelligence and work together to strike extremist targets. Yet deep distrust exists between the two. Just last week a Russian fighter jet conducted what the U.S. called an "unsafe and unprofessional" intercept of a U.S. military reconnaissance aircraft over the Black Sea, at one point flying within 10 feet.

Kerry said on Friday that if both sides lay down arms, the cease-fire could represent a "turning point" in the five-year civil war, one that could open the path to a political resolution.

The city of Aleppo, once Syria's largest, will factor heavily into the success of this plan. Aleppo remains a heavily contested area and has become of the face of population displacement and the dire humanitarian crisis. Intense bombing there persisted this weekend.

The new plan calls on both sides to move back from areas of Aleppo and allow for the flow of much needed aide to the remaining civilian population.

The cease-fire is set to coincide with the the Muslim Eid al-Adha holiday. Negotiators are hopeful the holy day will inspire both sides to obey the terms.

With about four months in office, it may be the Obama administration's last effort to bring an end to the war. The Obama administration chose in 2013 not to strike Assad's government, while all along maintaining the belief that he cannot remain in power. Obama also chose not to attack Assad after the dictator crossed the administration's "red line" by using chemical weapons on his people in 2013.

It is estimated that as many as half million people have died inside Syria during five years of civil war.