In a further reflection of the complicated terrain, Turkey's president said Wednesday that a U.S.-backed Syrian Kurdish militia group - which Turkey regards as a terror organization - should also be kept outside of the scope of the agreement.
Fighters and civilians in opposition-held areas also said they did not trust the government or its main allies, Russian Federation and Iran, to stop a military campaign that in recent weeks has displaced tens of thousands of people and has included the bombing of hospitals and schools. The deal does not include Islamic State or the Nusra Front, an al Qaeda affiliate which is widely deployed in opposition-held areas.
It does not apply to so-called Islamic State, the al Nusra Front and other militants designated as terrorists by the UN Security Council.
Syria's Foreign Ministry on Tuesday announced that the Syrian government consents to observe a cessation of hostilities as agreed upon by the United States and Russian Federation.
It said the armed forces reserved the right to respond to any attack by opposition groups.
In northern Syria, the Islamic State on Tuesday captured the town of Khanaser, cutting supply lines for government forces between the northern city of Aleppo and central and western Syria.
The Pentagon is maintaining a certain skepticism regarding the upcoming ceasefire in Syria, despite a confirmation from Moscow that Syrian President Bashar al-Assad will comply.
The deal calls for a "cessation of hostilities" between forces loyal to President Bashar al-Assad and opposition groups that would take effect overnight Friday-Saturday in Damascus.
POOL via CNN
The White House said US President Barack Obama discussed the agreement to end violence in Syria with British Prime Minister David Cameron, German Chancellor Angela Merkel and the French president via videoconference on Tuesday.
Corker and other Republican senators chided Kerry for the lack of leverage the US has against Russian Federation if Moscow violates the terms of the agreement.
"The proof will be in the actions that come in the next days", U.S. Secretary of State John Kerry told the Senate Foreign Relations Committee in Washington, according to Reuters, adding a reference to a contingency plan in place that could be implemented if the deal did not hold.
But Damascus is warning that there will be "violations" from other groups. Igor Konashenkov, said the center, located at Syria's Hemeimeem air base which is hosting Russian warplanes, has received several requests for assistance from various opposition groups.
The ministry statement was carried by the official SANA news agency on Wednesday.
"By controlling Syria's borders, the entry of terrorists and the transfer of arms, financial, and logistical aid to terrorist groups should be blocked", he added.
Russia followed the comments with the release of a statement Wednesday saying al-Assad has reaffirmed his intent to follow the ceasefire agreement to Russian President Vladimir Putin.
As objectionable as Russia's involvement in Syria is, the only prospect for peace is through a negotiated cease-fire, humanitarian relief and a serious attempt at a negotiating a political resolution, said Sen.
Erin Andrews tearfully takes the stand
His was prison: He pleaded guilty to federal stalking charges and in 2010 was sentenced to more than 2½ years in prison. Andrews testified how she suffers from depression, anxiety and panic attacks on a daily basis because of the video.