VILNIUS (Reuters) - Lithuania, at the front line of growing tension between the West and Russia, barred construction of a data center last year over concerns it could be infiltrated by Russian intelligence, a Lithuanian security official said on Monday.

He said the government acted on concerns about plans by Arcus Novus, the Lithuanian-registered construction firm, to develop a data center to be rented out to businesses for cloud computer operations.

“We warned the government that, once the data center is connected by fiber-optic cable to Russia, it could be linked by the (Russian) Federal Security Service to its radio electronic reconnaissance network,” a spokesman for Darius Jauniskis, Lithuania’s counter-intelligence chief, said.

“The government acted on that information,” he said.

Arcus Novus is now suing the government in an effort to overturn the decision, according to Vidmantas Tomkus, the company’s CEO and a minority shareholder.

“It’s a bit laughable to claim that a ‘hostile’ data center would be connected to Russian security services, as Lithuania is already connected to Russia through fiber-optic cables, as is the rest of the world,” said Tomkus.

Fears for cyber security are growing in the three small Baltic republics - all European Union members - bordering Russia, their former Soviet overlord. Russian computer hackers are seen as the greatest threat to Lithuanian national security, its counter-intelligence agency said in a report last year.

Leaders of other Western countries including the United States and Germany have also voiced concern about state-backed Russian hackers trying to undermine democratic institutions. The Kremlin has denied any link with reported hacking incidents.

The Lithuanian cyber security chief told Reuters earlier that three cases of Russian spyware had been discovered in government computers since 2015, and there had been 20 attempts to infect them in 2016.

A 2014 law allows the Lithuanian government to block any investment in energy, transport, information technology and finance that it finds threatening to its national security.

The State Security Department said that it advised the government to block four such investments in 2015, including a proposed expansion at Vilnius airport by a Lithuanian businessman who is also developing an airport near Moscow.