Several of Syria's key opposition factions said Monday they were launching an armed response to what they alleged were regime "violations" of a ceasefire agreement in the war-torn country. 

"After the increase of violations by regime forces that included targeting displaced people and continuous bombing of residential neighbourhoods, we declare the start of the battle in response," said a statement signed by 10 armed rebel groups.

The truce, brokered by Russia and the United States, has seen violence dip significantly across Syria but fighting has recently flared in several regions, particularly around second city Aleppo.