Kerry added that although the US-Russia peace plan was flawed, it was better than experiencing sectarian violence on a daily basis, describing the new agreement as the last chance "to save a united Syria.", Sputnik reported.
"This renewed cessation of hostilities went into effect… at sundown in Syria a few hours ago," Kerry told reporters. "The earliest reports are that there is… some reduction in violence."
US Department of State John Kirby later said he was unaware if any groups in Syria had refused to abide by the deal, although he had seen reports that the opposition faction Ahrar al-Sham rejected calls to adhere to the cessation of hostilities.
On September 9, Kerry and Russian Foreign Minister Sergei Lavrov announced a new peace plan to address the conflict in Syria that called for a ceasefire to come into force on Monday. If the new ceasefire in Syria lasts for seven days, the United States and Russia will work together to establish a joint implementation center.
The agreement also includes the creation of a demilitarized zone around Aleppo to deliver humanitarian aid to the city, as well as close coordination of Russian and US airstrikes against the Jabhat Fatah Al-Sham, formerly known as the Nusra Front, and the Islamic State terrorist groups operating in Syria.