On 9 September, the Russian-backed administration ordered the evacuation into Russia of the population from Izium, Kupiansk and Velykyi Burluk.[63] Local residents later reported that at this point Russian soldiers in the area began to flee villages, leaving behind their weaponry, before Ukrainian troops even arrived.[64] Later in the day Ukrainian forces reached Kupiansk, a vital transit hub at the junction of several of the main railway lines supplying Russian troops at the front.[65] The Institute for the Study of War said it believed Kupyansk would likely fall in the next 72 hours.[66] In response to the Ukrainian advance, Russian reserve units were sent as reinforcements to both Kupiansk and Izium.[67]