On 21 February, the Ba'athist government began an operation to capture rebel-held Ghouta east of Damascus; the operation started with an intensive air campaign. On 7 April 2018, a chemical attack was reported in the city of Douma, with 70 people killed and 500 injured. On-site medics stated the cause of those deaths was exposure to chlorine and sarin gas. Following the incident, Syrian Ba'athist government forces entered and established control over the city of Douma. On 6 July, as a result of the Southern Syria offensive, which had begun in June, the Syrian Army backed by Russian forces reached the border with Jordan and captured the Nasib Border Crossing.