A Russian military convoy travelling towards the Ukrainian capital of Kyiv has grown from being 17 miles long earlier on Monday to 40 miles, a satellite company has said, Daily Mail reported.
Maxar Technologies, a private US satellite company, also said additional ground forces deployments and ground attack helicopter units were seen in southern Belarus, less than 20 miles north of the Ukraine border.
Maxar said the convoy stretches from the Antonov airbase, 17 miles north of Kyiv's city center, to just north of the Ukrainian town of Pribyrsk.
Pribyrsk is closer to the Ukraine-Belarus border and the failed nuclear reactor at Chernobyl than to Kyiv.
On Sunday, Maxar had measured the convoy -- then near Ivankiv, Ukraine -- at roughly 3.5 miles long, Daily Mail reported.
US intelligence officials told members of Congress on Monday
that they expect a second overwhelming wave of attacks to engulf Kyiv. Two people told CNN that the briefing detailed how they expect the sheer numbers of Russian troops to flatten the Ukrainian resistance, the report said.
Another source told the channel that Russia was likely to lay siege to Kyiv, and predicted ugly scenes of urban warfare, Daily Mail reported.
The line of vehicles is so extensive that it was not entirely captured in Monday's satellite imagery. In some areas, the vehicles are two to three rows deep.
It was not clear whether all vehicles in the convoy were headed for the same final destination, or whether the military forces would split up and encircle the capital.
US intelligence believes around 75 percent of Russian forces positioned on the borders with Ukraine are now inside the country.