KYIV, Ukraine — Russian troops on Wednesday took charge of the eastern Ukrainian town of Vuhledar, a bastion that had resisted intense attacks since Russia launched its full-scale assault in 2022.

The advance of Moscow’s forces, which control just under a fifth of Ukraine, has underlined Russia’s vast superiority in men and materiel as Ukraine pleads for more weapons from the Western allies that have been supporting it.

Ukraine’s eastern military command said it had ordered a…