on 27 august, as part of a wider campaign in central syria against isil, the syrian arab army, launched a major offensive against the city of deir ez-zor in an attempt to break the siege. on 3 september, pro-government forces broke through to the city's first lines of defense around 10 pm. two days later, the siege was broken. soon after, the syrian democratic forces (sdf) launched an offensive on isil positions east of the euphrates river on 8 september, with us and kurd officials announcing they would not allow the syrian arab army to descend across the euphrates. meanwhile, on 10 september, the syrian arab army broke the siege of the deir ez-zor military airport, after which they pushed to the south. concurrently the sdf broke through to the outskirts of the city on the other side of the euphrates and occupied the industrial zone and the main road. on 11 september, the syrian arab army and the pro-government media announced the beginning of an offensive and amphibious landing over the euphrates river, beginning with the installation of pontoon bridges and amphibians. the announcement in the pro-government media was that the military operation would be called the assad's jump on the occasion of the birthday of syrian president bashar al-assad. on 15 september, russian foreign ministry spokeswoman maria zakharova announced the beginning of an army offensive across the euphrates river, and a day later the russian air force bombed the positions of the sdf northeast of deir ez-zor. elsewhere, pro-government forces, with the support of russian air strikes, launched operations against deir ez-zor city's northwestern district. the same day, the syrian government announced the start of an offensive on al-bukamal and the complete closure of the border with iraq.