Civilian Members of a territorial defence unit fit their weapons to repel the Russian attacking forces in Kyiv, Ukraine, Saturday, Feb. 26, 2022. Credit: Mikhail Palinchak / AP

WASHINGTON, D.C. — A senior U.S. defense official says the United States estimates that more than 50 percent of Russian combat power arrayed along Ukraine’s borders has entered Ukraine. That is up from a U.S. estimate Friday that one-third of the Russian force had been committed to the fight.

The official, who spoke on condition of anonymity to discuss internal U.S. assessments, would not say how many Russian troops that amounts to inside Ukraine, but the U.S. had estimated the total Russian force arrayed near Ukraine at more than 150,000.

The official said advancing Russian forces were roughly 30 kilometers outside Kiev as of Saturday, and that an unspecified number of Russian military “reconnaissance elements” had entered the capital.

Meanwhile, Britain’s Defense Ministry said Saturday that “the speed of the Russian advance has temporarily slowed, likely as a result of acute logistical difficulties and strong Ukrainian resistance.”

“Russian forces are bypassing major Ukrainian population centers while leaving forces to encircle and isolate them,” the ministry said.