The cessation of hostilities is the result of talks between the United States and Russia as co-chairs of the International Syria Support Group, the two countries said in a joint statement.
The main opposition group in Syria, the National Coalition of Syrian Revolution and Opposition Forces, expressed "preliminary approval to reach a temporary truce," it said in a statement.
The opposition group also called for guarantees that Russia, Iran and sectarian militias would stop the fighting.
The terrorist groups operating in Syria -- ISIS and al Nusra Front -- are not included in the proposal.
U.S. Secretary of State John Kerry has been working with world powers to get a cessation, but the violence in Syria is unrelenting. Almost 200 people were killed over the weekend in multiple attacks, for which ISIS claimed responsibility, in the city of Homs and on the outskirts of Damascus.
Monday, Kerry called the draft document promising, but said it requires action to see it through.
"I am gratified to see the final arrangements concluded today for a cessation of hostilities in Syria and call on all parties to accept and fully comply with its terms," Kerry said in a statement. "If implemented and adhered to, this cessation will not only lead to a decline in violence, but also continue to expand the delivery of urgently needed humanitarian supplies to besieged areas and support a political transition to a government that is responsive to the desires of the Syrian people."
U.S., Russia to share information
In the joint statement, the United States and Russia said they plan to share information on the groups who are pledging to put down their arms. This is so that U.S., Russian and Syrian forces do not attack groups that are abiding by the cessation of hostilities.
"The Russian Federation and the United States will establish a communication hotline and, if necessary and appropriate, a working group to exchange relevant information after the cessation of hostilities has gone into effect," the statement said.
It reiterated that the agreement does not include ISIS, al Nusra Front and other terrorist organizations operating in Syria.
Setting benchmarks and monitoring the cessation of hostilities won't be easy, U.S. State Department spokesman Mark Toner said.
"There's not going to be any force on the ground or monitors on the ground to look at this, other than where we get information from in terms of intelligence, but also through NGOs reporting on the ground and journalists, frankly, who give feedback as to who's being hit by whom," he said.
The renewed talk of peace came after a violent weekend in Syria. Three bombers struck Damascus' Sayyidah Zaynab district, killing scores of people, according to Syria's state-run SANA news agency.
The Damascus blasts were near the revered Lady Zeynab Shia Muslim shrine, SANA reported. The agency said 178 others were wounded there, citing its reporter on the scene and local sources.
The London-based monitoring group Syrian Observatory for Human Rights reported two suicide bombers and a suicide car bomb were responsible for the Damascus attacks.
Regime stronghold attacked in Homs
In the earlier attacks Sunday, Homs Gov. Talal al-Barazi told SANA that two cars packed with "huge amounts of explosives" were detonated near a bus stop in central Homs.
Dozens were killed, and the Syrian Observatory for Human Rights said more than 100 others were wounded.
The bombings were in the al-Zahraa district, a regime-controlled neighborhood that is predominantly home to members of Syrian President Bashar al-Assad's Alawite sect.
Al-Barazi said the attacks were aimed at the support base of the Syrian government, as the country's army made gains against rebels around the country.
The blasts targeted students and government employees heading to work, the state-run TV station al Ikhbaria reported.
Images from the scene showed dozens of destroyed vehicles and severe damage to nearby buildings.
More than 250,000 people have been killed, more than 1 million injured and more than half of Syrians displaced since the country's civil war began in 2011, according to the United Nations.