Sarcastically, Ukrainian President Petro Poroshenko said the new bridge "will definitely be handy for the occupants when they have to urgently leave our Crimea".
The annexation of the peninsula in 2014 was condemned by Kiev and the West as an illegal land grab but applauded in Russian Federation.
The spokesperson for the European External Action Service said in a statement on Tuesday that the bridge was "another violation of Ukraine's sovereignty and territorial integrity".
Russian President Vladimir Putin, driving a truck, unveiled the auto section of a new road-and-rail bridge linking Russia to the annexed Crimean peninsula on Tuesday, defying Ukraine which said the move showed cynical disregard for global law.
A view of the new bridge linking Russian Federation and the Crimean peninsula prior to its opening ceremony near Kerch, Crimea, May 15, 2018.
"I welcome the formal decision of the EU Council to impose sanctions against five individuals responsible for the unlawful conduct of the presidential elections in the temporarily occupied Crimea and Sevastopol", - he wrote.
Many in Russia saw the bridge as a move toward restoring Moscow's rule over a historically Russian region.
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The Parc Des Princes side are also planning to make their loan deal for Monaco's Kylian Mbappe a permanent transfer at £165m. Speaking to reporters after the ceremony, he said: "I am very touched and very happy with our season".
Ukraine has condemned the project, which cost 228 billion rubles ($3.7 billion). "Many didn't believe these plans were possible", Kremlin spokesman told reporters on Tuesday ahead of the ceremony.
The construction is one of Putin's legacy projects, after the massive renovation of the Black Sea city of Sochi for the 2014 Winter Olympics and the 2012 opening of the world's longest cable-stayed bridge in the far eastern city of Vladivostok.
Ukraine, which along with most of the worldwide community has not recognised Russia's annexation of Crimea, condemned the project, which was personally championed by Putin.
"This is an extremely important day from this point of view and in a practical sense and in symbolic terms". The bridge was completed six months ahead of schedule.
The bridge is set to be opened to cars on Wednesday.
At the other end of the 19-kilometer bridge, in Crimea, Putin attended a brief open air show.