İzmit was occupied by the United Kingdom on 6 July 1920, during the Turkish War of Independence. The British left it to Greece on 27 October 1920. İzmit was re-taken by the Turks on 28 June 1921. As of 1920, the British reported that the city had a population of about 13,000. In 1920–1921 atrocities were committed in the city and its surroundings during the Greco-Turkish War (1919–1922) against the civilian population. An Allied report (on 1 June 1921) stated that a large number of excesses were committed by both sides during the last year, while the Turkish atrocities in the Izmit peninsula "have been more considerable and ferocious than those on the part of the Greeks".