BRUSSELS -- The European Union has added six Russian companies involved in the recent construction of the Kerch Strait bridge linking Russia with the Crimean Peninsula to its sanctions list.

The decision was made by the European Council on July 31 following the EU ambassadors' approval earlier this month.

The EU has now frozen the assets of a total of 44 entities from Russia and Ukraine since Moscow's seizure of Ukraine's Crimea region in March 2014 and its support for separatists in a conflict that has killed more than 10,300 people in eastern Ukraine since April 2014.

In addition, 155 individuals from both countries are subject to EU asset freezes and travel bans.

Three of the Russian companies newly included in the EU sanctions list -- Mostotrest, Stroygazmontazh, and its subsidiary Stroygazmontazh Most – are owned by Arkady Rotenberg, a businessman close to President Vladimir Putin.

Rotenberg had previously been included in the list of individuals sanctioned by the EU.

Construction firm CJSC VAD, engineering firm GPSM, and the Zaliv Shipyard are the three newly sanctioned Russian entities.

The European Council said in a statement that the six companies "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."

Ukrainian Foreign Minister Pavlo Klimkin welcomed the EU move, writing on Twitter, "Important warning also for European businesses not to go down same slippery slope."

Russian Foreign Ministry spokeswoman Maria Zakharova denounced the "subversive policy directed against the residents of Crimea."

Meanwhile, a spokesman for Rotenberg quoted the businessman as brushing aside the sanctions. "We're all proud of our work and if someone doesn't like it that's not our problem," the spokesman quoted Rotenberg on a social media post as saying.

The 19-kilometer Kerch Strait bridge was opened for cars and buses in May. It contains a four-lane highway and two lines of railway tracks that are still under construction. The $3.7 billion Russian construction project began in 2016.

With reporting by Interfax and Reuters