Russia does not fully control these regions and has been losing ground to Ukraine's forces.
Biden said he'd hold talks with Putin if the Russian leader expresses a desire to end the war.
Russian forces retreated from Kherson, the first major city Russia captured after launching the invasion in late February, last month.
Ukrainian President Volodymyr Zelensky has been clear that he would not agree to any peace deal that saw Kyiv cede territory to Russia.
Zelenskyy has cited the restoration of Ukraine's territorial integrity as a condition for talks with Russia to begin.
The president also said the only way for the Ukraine war to end is for Putin to recall his forces.
Biden on Thursday said "it's sick" what Putin has unleashed on Ukraine as he railed against Russia for repeatedly striking civilian areas in Ukraine. »