Kerry says US-Russia agreement could be 'turning point' in Syria conflict

The United States and Russia announced early Saturday a breakthrough agreement on Syria that foresees a nationwide cease-fire starting early next week, followed by an unlikely new military partnership between the rival governments targeting the Islamic State and al-Qaida.

At a joint news conference after a marathon day of negotiations, U.S. Secretary of State John Kerry said the plan can reduce violence in Syria and lead to a long-sought political transition, ending more than five years of bloodshed. He called the deal a potential "turning point" in the conflict, if implemented by Syria's Russian-backed government and U.S.-supported rebel groups.

The cease-fire begins at sundown Monday, Kerry said, coinciding with the Muslim Eid al-Adha holiday. The nationwide cease-fire in Syria comes after more than five years of warfare and as many as 500,000 deaths.

Kerry's negotiating partner, Russian Foreign Minister Sergey Lavrov, confirmed the agreement and said it could help expand the counterterrorism fight and aid deliveries to Syrian civilians. He said Syrian President Bashar Assad's government was prepared to comply with the arrangement.

Previously, neither side had succeeded in doing its part despite months of diplomacy. And the task was becoming even more difficult as fighting rages around the divided city of Aleppo, Syria's most populous and the new focus of the conflict. Assad's government appeared to tighten its siege of the former Syrian commercial hub on Thursday, following several gains over the weekend, which could make it harder for the U.S. and Russia to find a compromise that ends the fighting. Forty days of fighting in Aleppo has killed nearly 700 civilians, including 160 children, according to a Syrian human rights group.

Skeptics remain on Russia, Saudi Arabia oil pledge

In addition to those killed, Syria's conflict has chased millions of people from their homes, contributing to Europe's worst refugee crisis since World War II. Amid the chaos of fighting between Syria's Russian-backed government and U.S.-supported rebels, the Islamic State group has emerged as a global terror threat.

Russia's military intervention last year has shored up Assad's position against the variety of militant groups he is facing. Although Russia claims to be targeting IS and the Nusra Front, al-Qaida's Syria affiliate, the Obama administration says the majority of its air strikes have hit "moderate" rebels backed by the United States and its Arab partners. Russia has been keen to unify its counterterror campaign with that of the United States, but up to now Washington has held back.

This story is developing. Please check back for further updates.