Ukraine troops have blown up two primary bridges that Russian troops used to access occupied territory as the country’s top soldier said Saturday that one fifth of invading ground forces have been “destroyed” with the conflict nearing its sixth month.

The Antonivsy road bridge and the Kherson rail bridge over the Dnipro River were heavily damaged in attacks earlier this week and are “likely unusable for heavy military vehicles,” according to a report from British intelligence released Saturday. That could mean Russian soliders are stuck with limited options for new supplies or weapons to reach them.The two primary road bridges giving access to the pocket of Russian occupied territory on the west bank of the Dnipro in Kherson Oblast are now probably out of use for the purpose of substantial military resupply,” the British intelligence briefing said. “On 10 August 2022, Ukrainian precision strikes likely rendered the road crossing of the Dnipro River at Nova Kakhovka unusable for heavy military vehicles. In recent days, Russia has only succeeded in making superficial repairs to the damaged Antonivsky road bridge, which likely remains structurally undermined.”Even if Russia were to make repairs to the bridges, they will remain “a key vulnerability,” the report said. “Ground resupply for the several thousand Russian troops on the west bank is almost certainly reliant on just two pontoon ferry crossing points,” said the British report. “With their supply chain constrained, the size of any stockpiles Russia has managed to establish on the west bank is likely to be a key factor in the force’s endurance.”Ukrainian troops have “destroyed” one fifth of Russian ground forces in the country, Ukrainian Armed Forces chief General Valeri Zaluzhnyi told US Chairman of the Joint Chiefs of Staff Gen. Mark Milley during a phone call Saturday.Western officials estimate that Russia has lost up to 20,000 soldiers in the conflict, which began when Russia invaded Ukraine on Feb. 24. The Ukrainian government has not released reports of losses, citing efforts to boost the morale of their country’s fighters.

Separately, Ukrainian President Volodymyr Zelensky called on world leaders to restrict visas for Russian nationals and declare Russia a state sponsor of terrorism.

“There must be a guarantee that Russian killers and state terror guides will not use Schengen,” said Zelensky in a video address Friday. “You cannot destroy the very idea of Europe, our common European values…You cannot turn Europe into a supermarket that does not matter who enters.”

This week, Latvia’s parliament declared Russia a state sponsor of terrorism for violence against civilians in Ukraine, while Estonia approved restrictions on tourist visas for Russian citizens entering the country. On Friday, Kyiv called on other countries to do the same, according to the Wall Street Journal.