KYIV, Ukraine (AP) – The British Defense Ministry says Russian forces have taken the Ukrainian city of Kreminna after days of street-to-street fighting. Moscow also unleashed attacks against rail and fuel installations far from the front lines. Russian Foreign Minister Sergei Lavrov warned Ukraine against provoking World War III, saying on Russian TV that the threat of a nuclear conflict “should not be underestimated.” The British military did not say how it knew Kreminna in the Lukansk region had fallen. It also described heavy fighting as Russian forces tried to advance toward other cities in Moscow’s new eastern offensive. Lavrov’s comments came after U.S. Defense Secretary Lloyd Austin said the U.S. wants to see Russia weakened “to the point where it can’t do things like invade Ukraine.”