Ukraine had previously suggested some Russian units might be leaving.
Russia took Kherson in the early days of the war, but has recently come under pressure as Ukrainian troops advance along the Dnipro River.
Russian authorities in the city have ordered thousands of civilians to evacuate.
Ukraine’s spy chief said Russian military is sending in more troops and preparing the streets for defense, adding that the removal of citizens is a pretense to save face in case the city falls to Ukraine.
