Putin tightens infrastructure security after blast on bridge

An explosion Saturday caused the partial collapse of a bridge linking the Crimean Peninsula with Russia, damaging an important supply artery for the Kremlin's faltering war effort in southern Ukraine and hitting a towering symbol of Russian power in the region.

Nobody immediately claimed responsibility for the blast, which killed three people. The speaker of the Russian-backed regional parliament in Crimea accused Ukraine, but Moscow didn't apportion blame. Ukrainian officials have repeatedly threatened to strike the bridge and some lauded the destruction on Saturday, but Kiev stopped short of claiming responsibility.

The explosion, which Russian authorities said was caused by a truck bomb, risked a sharp escalation in Russia's eight-month war, with some Russian lawmakers calling for President Vladimir Putin to declare a "counterterrorism operation," shedding the term "special military operation" that had downplayed the scope of fighting to ordinary Russians.

Putin signed a decree late Saturday tightening security for the bridge and for energy infrastructure between Crimea and Russia, and put Russia's federal security service, the FSB, in charge of the effort.

Hours after the explosion, Russia's Defense Ministry announced that air force chief Gen. Sergei Surovikin would now command all Russian troops in Ukraine. Surovikin, who this summer was placed in charge of troops in southern Ukraine, had led Russian forces in Syria and was accused of overseeing a bombardment that destroyed much of Aleppo.

Moscow, however, continues to suffer battlefield losses.

On Saturday, a Kremlin-backed official in Ukraine's Kherson region announced a partial evacuation of civilians from the southern province, one of four illegally annexed by...