Estonia warned on Thursday that Russia appears willing to defend with military force its shadow fleet of aging tankers dodging international sanctions to keep oil revenue and equipment flowing, even through the territorial waters of European countries.

A Russian military jet "violated NATO territory" after the Estonian Navy made an attempt to intercept a tanker thought to belong to Moscow's "shadow fleet," Estonian Foreign Minister Margus Tsahkna said on May 15 in comments reported by Reuters.

A Russian Su-35 violated Estonian airspace on May 13, 2025, to disrupt efforts to inspect a ghost fleet tanker, escalating tensions in the Baltic Sea region.