The Ukrainian military’s “direct attacks” against the Russian convoy heading toward the capital city of Kyiv have slowed it down, a U.S. senior defense official told reporters on Friday.

Russian troops have invaded Ukraine on three specific axes, with one coming from Belarus, which borders Ukraine to the north and provides a closer path to Kyiv, and they have faced resistance from Ukrainian forces. The Russian military remains roughly 15 miles outside the city, while the senior defense official told reporters on Thursday that the Pentagon hadn’t seen it make “appreciable” gains in “2-3 days,” while affirming that this analysis hadn’t changed by the same time Friday.