The head of Lithuania's National Cyber Security Center, Rytis Rainys, said on Tuesday that consumers should stop using a well-known Russian taxi-booking app, citing concerns that it was illegally harvesting user data.

The app is technically based in Amsterdam, but is part of Yandex, one of Russia's most successful tech companies. As a search engine, Yandex accounts for about 65 percent of all Russian internet searches and operates a number of popular map and transit apps.

Rainys told the Associated Press that after running tests on the app, authorities "strongly recommend against installing and using it, especially those working in state offices."

Yandex reportedly requires access to your phone's camera, microphone, and local data network.

It entered the Lithuanian market on Thursday, and has said it has about 300 cars operating in the capital, Vilnius.

Yandex: Accusations are groundless

Yandex's global strategy director, Aram Sargsyan, denied the allegations, telling the Baltic News Service that the firm "processes and stores data of European Union users strictly according to EU regulations."

Sargsyan added that they were "open and ready to any necessary checks. Any accusations against us don't have any grounds."

US-based ride-hailing app Uber recently merged with Yandex in the Russian market, ceding control to the Russian firm, which now owns about 59 percent of the joint venture.