Baikonur (Kazakh: Байқоңыр, بايقوڭىر, translit. Baıqońyr ; Russian : Байконур , translit. Baykonur ), formerly known as Leninsk (also, see Tyuratam ), is a city of republic significance in Kazakhstan on the Northern bank of the Syr Darya river, rented and administered by the Russian Federation .