There were other claimants, naturally. Ermak's expedition to Siberia in the 1580s was one of conquest rather than exploration. He managed to defeat forces of the Siberian Khanate and gain a foothold for further expansion eastward. Fighting continued with Mongolia and China for hundreds of years. Even in the 20th century, there were still attempts by various Chinese warlords during the 1920s and the Japanese in the 1930s to take Siberian territory from the Soviet Union.