Ukraine’s military is confronting a “critical” situation in the country’s northeast, facing troop shortages as it tries to repel a Russian offensive that has been advancing for several days, a top Ukrainian general said on Monday. Russian troops surged across the border last week to open a new line of attack near Kharkiv, Ukraine’s second-largest city after Kyiv, capturing at least nine settlements and villages and forcing thousands of civilians to flee. “The situation is on the edge,” Gen. Kyrylo Budanov, the head of Ukraine’s military intelligence agency, said in a video call from a bunker in Kharkiv. “Every hour...