Germany has stopped a major deal to provide a fully equipped training camp to Russian forces due to the crisis in Ukraine, the government said Monday.

Vice Chancellor and Economy Minister Sigmar Gabriel said he has withdrawn his authorization for the training camp project, which had already been put on hold in March after Moscow's annexation of Ukraine's Crimea region.

He confirmed a report in the daily Sueddeutsche Zeitung citing the decision to scrap the contract, reportedly valued at 100 million euros ($134 million). "We consider it indefensible in the current situation," a ministry spokeswoman said.

Russia previously called the decision to halt the arms deal "unconstructive," accusing Berlin of acting under pressure from the US.

German defense group Rheinmetall, the contractors for the military training camp, had said in March that the company would fulfill its contractual obligations to build the center, which German media said would train 30,000 soldiers a year.

The camp was to have been built in the Volga region, and was scheduled to open later this year.

The ministry spokeswoman said that the government was in contact with the firm, which will have the opportunity to claim financial damages for the scrapping of the contract.

Separately, Russia said on Monday that more than 400 Ukrainian soldiers had crossed over onto its territory to avoid fighting with pro-Kremlin insurgents in the east.

A security official said 438 troops had asked Russian authorities to open a "humanitarian corridor" overnight because they were no longer able to defend their positions.

The Ukrainian military confirmed that an undisclosed number of troops had crossed into Russia but denied Moscow media reports that they were seeking permanent refugee status.

Russia announced military exercises near the border with Ukraine on Monday in a show of strength as the Ukrainian army recaptured more territory from separatists in eastern Ukraine.