Russia seized Crimea from Ukraine in 2014 during an uprising which toppled Ukraine's pro-Russian president. The West condemned the move as an illegal annexation and imposed sanctions on Moscow.
The $3.6 billion bridge across the Kerch strait, part of which was unveiled by Russian President Vladimir Putin in May, has drawn strong rebukes from the EU which says it is a further violation of Ukraine's sovereignty.
The six companies cited in Tuesday's statement from the Council of the European Union include construction firms PJSC Mostotrest
The firms will have their assets in the EU frozen and EU persons and entities will not be able to make funds available to them, the Council said.
"Through their actions they supported the consolidation of Russia's control over the illegally annexed Crimean peninsula, which in turn further undermines the territorial integrity, sovereignty and independence of Ukraine," the Council said.
Ukraine's foreign minister Pavlo Klimkin said he welcomed the additional sanctions.
"Important warning also for European businesses not to go down same slippery slope," Klimkin wrote on Twitter.
The other companies targeted are engineering firm GPSM, Zaliv Shipyard and construction groups SGM and Stroygazmontazh Most OOO.
