New satellite images published Saturday show Russia has massed troops in the annexed Crimean Peninsula in recent days.
Private Israeli intelligence firm ImageSat International (ISI) said some of the military vehicles — including tanks, armored personnel carriers and rocket launchers — were seen outside of staging grounds, “possibly preparing for movement soon.”
The buildup in Crimea occurred within the past four days, according to ISI.
Imagery from February 15 shows the area near the town of Novoozerne completely empty.
ISI said the buildup of the forces in the area was to allow Russia to invade southern Ukraine.
The US, which estimates that Russia has placed more than 150,000 troops near Ukraine’s borders, has observed significant movements since Wednesday, a US defense official said, insisting on anonymity.
“Forty to fifty percent are in an attack position. They have uncoiled in tactical assembly in the last 48 hours,” the official told reporters.
Tactical assembly points are areas next to the border where military units are set up in advance of an attack.
The official said Moscow had massed 125 battalion tactical groups close to the Ukraine border, compared to 60 in normal times and up from 80 at the beginning of February.
The Russians have never given a figure for the deployment along the border with Ukraine, nor how many are taking part in ongoing drills with neighboring Belarus.
Separatist leaders in eastern Ukraine ordered a full military mobilization on Saturday, while Western leaders made increasingly dire warnings that a Russian invasion of its neighbor appeared imminent.
Speaking to Israeli TV, Denis Pushilin, the head of the pro-Russia separatist government in Ukraine’s Donetsk region said it would call for Russia’s help if the situation escalates.
“It is very likely that Ukraine intends to initiate a military confrontation and go on the offensive,” Pushilin told the Kan public broadcaster.
“The ball is in Ukraine’s court, and we do not rule out that in certain circumstances, if civilians are killed, we will have to seek Russia’s help,” he added.
Ukraine’s military said two of its soldiers died in firing from the rebel side on Saturday.
By Saturday morning, the separatists in the Luhansk and Donetsk regions, which form Ukraine’s industrial heartland known as the Donbas, said that thousands of residents of the rebel-controlled areas had been evacuated to Russia.