In July 1737, Austria entered the war against the Ottoman Empire, but was defeated a number of times, amongst others in the Battle of Banja Luka on 4 August 1737, Battle of Grocka at 18, 21–22 July 1739, and then lost Belgrade after an Ottoman siege from 18 July to September 1739. In August, Russia, Austria and Ottoman Empire began negotiations in Nemirov, which would turn out to be fruitless. There were no significant military operations in 1738. The Russian Army had to leave Ochakov and Kinburn due to the plague outbreak.