Islam Times: A formal announcement is due to be made at the Arab League headquarters in the Egyptian capital, Cairo, on Wednesday.
The agreement comes as thousands of Syrians held a demonstration in support of the government of President Bashar al-Assad in the northeastern city of Deir al-Zour on Tuesday.
Demonstrators expressed their support for the reforms promised by the Syrian president. They also chanted slogans against foreign intervention in the country.
President Assad said on Sunday that any intervention by Western powers to divide the country would break up the entire region.
Syria has been experiencing unrest since mid-March, with demonstrations being held both against and in support of President Assad.
Hundreds of people, including members of the security forces, have been killed in the turmoil.
While the opposition and Western countries accuse security forces of being behind the killings, the government blames outlaws, saboteurs and armed terrorist groups for the deadly violence, saying that the unrest is being orchestrated from abroad.