LONDON—Internet connectivity in Ukraine has been affected by the Russian invasion, particularly in the southern and eastern parts of the country where fighting has been heaviest, internet monitors said on Saturday. Russian forces captured the southeastern Ukrainian city of Melitopol on Saturday, Russia’s Interfax news agency reported, as Moscow launched coordinated cruise missile and artillery strikes on several cities, including the capital Kyiv. Connectivity to GigaTrans, Ukraine’s main internet provider, dropped to below 20 percent of normal levels before returning to higher levels in the early hours of Friday morning, according to internet monitoring organization NetBlocks. “We currently observe national connectivity at 87 percent of ordinary levels, a figure that reflects service disruptions as well as population flight and the shuttering of homes and businesses since the morning of the 24th,” Alp Toker, director of NetBlocks, told Reuters. “While there is no nation-scale blackout, little is being heard from the …