Russia says talks are under way for agreement on a freeze in fighting in the northwestern Aleppo Province where deadly militant attacks have escalated over the past few days.
Lieutenant General Sergei Kuralenko, head of Moscow's coordination center in Syria, said on Sunday that the "calm" around Damascus has also been extended for another 24 hours.
"Currently active negotiations are underway to establish a 'regime of silence' in Aleppo Province," Kuralenko said.
Meanwhile, the Syrian Armed Forces Command in a statement on Sunday announced "silence regime" extension in Damascus region for 24 hours.
Syria started enforcing a “silent period” in parts of Latakia and Damascus regions from 1:00 a.m. (2200 GMT) on April 30.
"The established ‘silence regime’ in Damascus and eastern suburbs has been extended for additional 24 hours," the statement said.
Syria’s offensive in Aleppo is based on a UN Security Council resolution which accepts Syria’s right to fighting terrorists.
Syria’s official SANA news agency said on Saturday that at least 25 people were killed in militant rocket attacks on the two residential neighborhoods of Neel and Hamadaniyeh over the past 24 hours.
The Takfiri Daesh militants and al-Nusra Front are excluded from a “cessation of the hostilities” agreement reached in late February as an attempt for facilitating peace talks.
The truce, which is sponsored by the United States and Russia, is still officially in place in many parts of Syria despite surging violence in Aleppo, which has been a flashpoint over the past weeks.
Aleppo has been divided between the government forces and militants since 2012, a year after the conflict broke out in the Arab country. Dozens have been killed in renewed clashes over the past few days as warnings are high that a human tragedy may unfold in the city.
Since March 2011, the United States and its regional allies, in particular Saudi Arabia, Qatar and Turkey, have been conducting a proxy war against Syria.
According to a February report by the Syrian Center for Policy Research, the conflict has claimed the lives of over 470,000 people, injured 1.9 million others, and displaced nearly half of the pre-war population of about 23 million within or beyond Syria’s borders.