Almost 100,000 Russian troops have amassed on Ukraine’s border, a top Ukrainian defense official said on Thursday.

The figure is much higher than U.S. military estimates.

“Russian troops aren’t in Crimea only. They’re along all Ukrainian borders. They’re in the south, the east and the north,” Andriy Parubiy, chairman of Ukraine’s national security council, said via webcast from Kiev.

Russia is plotting to incite separatist sentiment in other areas after its successful intervention in the Crimea region, he told the Atlantic Council, a Washington-based think tank.

The deployed forces are well-trained special forces, he said, adding that Kiev fears a potential Russian invasion of the country’s east any day now.

A senior U.S. defense official expressed scepticism at Parubiy’s estimate of the number of Russian forces.

“That sounds too high,” the official, who spoke on condition of anonymity, told Agence France Presse.

The Pentagon said more than 20,000 Russian troops have been deployed along the border with Ukraine, included airborne units and armored vehicles.

Parubiy said his country supported sanctions against Russia imposed by Western countries, and appealed for a military partnership to send a signal to Moscow over its actions.

“We’re calling on our partners to hold a common military exercise” that would “show that the cooperation and partnership is still there,” he said.

Parubiy also urged “visible support, visible presence of our partners” at this moment of crisis.

(Al Arabiya with AFP)