(Bloomberg) -- Latvia blocked a Turkish bid to build a high-speed rail link connecting the three Baltic states, choosing instead a group of European Union companies for the biggest regional infrastructure project in at least three decades.

The prime ministers of Latvia, Lithuania and Estonia signed an agreement in 2017 to build the Rail Baltica project. It envisages 700 kilometers (440 miles) of track, stitching together the three nations’ capitals and the Lithuanian city of Kaunas before heading on to the Polish border. 

Turkey’s Dogus Insaat and IC Ictas Insaat didn’t make it to the final round of the tender to build the railbed for Latvia’s section, even though their offer was about €500 million ($535 million) lower than the winning bid, according to Eiropas Dzelzcela linijas, the state-owned company overseeing the project. 

The reason for their exclusion was a “negative” opinion from the Latvian State Security Service, Linda Pastare, a spokeswoman, said by email Tuesday. 

The decision was first reported late Sunday by Latvia’s public broadcaster, which said that one of the Turkish builders had a history of projects in Russia. The Turkish companies intend to appeal the exclusion, LTV said.

Latvia, a member of the EU and NATO, has been one of Europe’s harshest critics of the Kremlin’s invasion of Ukraine, advocating tougher sanctions against Moscow. 

The Baltic country instead chose a French, Polish and Italian joint venture to build the track, with a proposed contract price of €3.7 billion. 

“Our joint venture submitted the most favorable financial offer, which was approved by the employer after detailed clarification stages including both technical and financial evaluations,” IC Ictas said in response to questions from Bloomberg. The Latvian security service and Dogus Insaat didn’t immediately reply to requests for comment. 

--With assistance from Taylan Bilgic.

(Updates with company comment in final paragraph.)

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