A senior official at the US Defense Department says Russia's advance on Ukraine's capital Kyiv has been slower than the Kremlin anticipated, due to stiff Ukrainian resistance.

Pentagon analysis shows Russia continuing its three-pronged invasion, including the route from neighboring Belarus to Kyiv, with the aim of taking control of heavily populated areas.

The official told reporters on Friday that the advance has been slower than Russia anticipated and that none of the population centers have been taken. He added Ukraine's air defense system is still working.

The official also observed that Russia has only moved into Ukraine about one third of the troops it had amassed near the border.
The official said thousands of Russian troops may have landed in the west of Mariupol, in the eastern region of Donetsk along the Sea of Azov.

Observers say the situation could change rapidly.

Meanwhile US State Department spokesperson Ned Price tweeted on Friday that "the Ukrainian people are showing strength and determination" in response to the Russian attack.

He continued that "Ukrainian soldiers demonstrate incredible bravery."

He stressed the need for continued US support for Ukraine's defense capabilities.

Price also wrote that "Russia is creating a disinformation campaign by publicizing false reports about the widespread surrender of Ukrainian troops."

He said Russia hopes to use disinformation to demoralize Ukrainian soldiers and citizens, and induce their surrender.