army command said it will suspend military operations to mark the Muslim holiday of Eid al-Adha,
declaring a ceasefire from Friday morning to Monday but saying it reserved the right to respond to rebel attacks and bombings.
It said it would also respond to "terrorist groups trying to reinforce their positions by arming themselves and getting reinforcements" as well as neighboring countries facilitating the smuggling of fighters across borders during that period.
Syria: Explosion hits Damascus, at least 10 killed
- Syria's Assad agrees to holiday ceasefire
Turkey, Germany call for truce in Syria
A Free Syrian Army commander said on Thursday rebels will honor the ceasefire but demanded the release of detainees by Friday.
However, the spokesman of Islamist Ansar al-Islam, Abu Moaz, said his fighters will not commit to the lull. Abu Moaz also said the fighters doubt the government will honor the truce.
On Wednesday, International mediator Lakhdar Brahimi said the Syrian government had agreed to a ceasefire in the war with rebels during Eid al-Adha.
"After the visit I made to Damascus, there is agreement from the Syrian government for a ceasefire during the Eid," Brahimi told a news conference at the Cairo-based Arab League.
The holiday starts on Thursday and lasts three or four days. Brahimi did not specify the precise time period for a truce.
A previous ceasefire arrangement in April collapsed within days with both sides accusing the other of breaking it.