LONDON

Britain on Thursday warned Russia that it would be a “disaster” if it launches any incursion into Ukraine.

“If Russia were to make any kind of incursion into Ukraine on any scale whatever I think that would be a disaster for not just for Russia, it would be a disaster for the world,” Prime Minister Boris Johnson said.

Johnson's comments came during a visit to Taunton, southwest England.

“The UK stands squarely behind the sovereignty and integrity of Ukraine,” Johnson reiterated his country's support to Ukraine.

Russian President Vladimir Putin “must not be allowed to rewrite the rules” of international relations, Johnson told his Cabinet members earlier this week.

He said the UK is “doing everything possible to support the Ukrainian people in the face of a disinformation campaign from Russia aimed at undermining its sovereign neighbor.”

“The UK remains open to further talks with Russia,” Johnson added.

British Foreign Secretary Liz Truss earlier this month said any Russian military incursion into Ukraine would be a “massive strategic mistake and would come at a severe cost.”

The UK has supplied Ukraine with “light, anti-armor, defensive weapon systems” amid the Russian military buildup on its border, Britain's Defense Secretary Ben Wallace said earlier this week.

Russia, Ukraine, and NATO have stepped up military exercises as tensions have intensified in recent weeks, with Kyiv openly accusing Moscow of planning an invasion.

Russian forces entered the Crimean Peninsula in February 2014, with Putin formally dividing the region into two separate federal subjects of the Russian Federation the following month.

According to the UN, fighting between Ukrainian government forces and pro-Russian separatists in Ukraine's eastern Donbass region has seen more than 13,000 people killed since 2014.

The region is one of several sources of friction between Russia and Ukraine.