Romania and Ukraine want Western allies to step up their military presence in the Black Sea as they accuse Russia of militarising the region, reports Defense News. Defense News, an independent news source for defence decision-makers, obtained letters from the Romanian and Ukrainian ambassadors to the United States.

The overlapping warnings — that Russia’s aggression and deployments of missile systems in Crimea threaten allies more broadly — came in dispatches from each country’s ambassador to the U.S. Senate’s Europe and Regional Security Cooperation subcommittee ahead of its Black Sea hearing last week.

The warnings came after U.S. Defense Secretary Lloyd Austin visited Romania in October as part of a three-country tour to reassure Black Sea allies on security issues amid ongoing tensions with Russia. According to the Pentagon, Austin’s visit, which in addition to Romania included visits to Georgia and Ukraine, is meant to “reassure allies and partners of America’s commitment to their sovereignty in the face of Russian aggression”.