(Bloomberg) — Russian computer attacks have become more brazen and more destructive as the country grows increasingly at odds with the U.S. and European nations over military goals first in Ukraine and now Syria.

Along with reported computer breaches of a French TV network and the White House, a number of attacks now being attributed to Russian hackers and some not previously disclosed have riveted intelligence officials as relations with Russia have deteriorated. These targets include the Polish stock market, the U.S. House of Representatives, a German steel plant that suffered severe damage and The New York Times.

U.S. officials worry that any attempt by the Russian government to use vulnerabilities in critical infrastructure like global stock exchanges, power grids and airports as pressure points against the West could lead to a broader conflict, according to two people familiar with the debate inside government and who asked to not to be named when discussing intelligence matters. When NATO officials met last week, they voiced alarm about Russia's rapid involvement in Syria, including the firing of cruise missiles, and vowed the biggest reinforcement of their collective defense since the end of the Cold War.