Arab League chief Nabil al-Arabi would head to Damascus bearing "an initiative to solve the crisis" in Syria, a statement said early Sunday after a meeting of Arab foreign ministers in Cairo.
It was not clear when Arabi would visit Syria but Russia also announced it was sending a top envoy to the Syrian capital on Monday, Itar-Tass news agency reported.
Meanwhile Syrian authorities, in a statement carried by SANA news agency, warned protesters to stay away from demonstrations in the main streets of the capital being urged on Facebook.
"The interior ministry asks citizens not to respond to calls on social networks to take part in demonstrations and gatherings in the principal squares of Damascus, for their own safety," it said.
The Syrian Revolution 2011, a key driver of the protests, meanwhile called for prayers on Sunday "in churches and in mosques for the martyrs of freedom," in a message on its Facebook page.
The United Nations says more than 2,200 people have been killed since anti-regime protests began in mid-March.
The latest bloodletting claimed two lives in Syria on Saturday, the Syrian Observatory for Human Rights reported.
It said a demonstrator was killed and 10 were hurt when club-wielding security forces attacked a group of people leaving prayers at the Rifai mosque in the capital's western quarter of Kafar Susseh.
The imam of the mosque, Osama al-Rifai, was among the wounded.