KYIV, Ukraine (AP) – Russia is vowing to continue its bloody offensive in Ukraine as the war’s sixth week wraps up Wednesday. Vladimir Putin insisted the invasion was going according to plan despite a major withdrawal and significant losses. Thwarted in their push toward Ukraine’s capital of Kyiv, Russian troops focused on the eastern Donbas region. Meantime, Ukraine is investigating a claim that a poisonous substance had been dropped on its troops there. It was not clear what the substance might be, but Western officials warned that any use of chemical weapons by Russia would be a serious escalation of the already devastating war.