LONDON — Russian hackers used a bug in Microsoft Windows to spy on several Western governments, NATO and the Ukrainian government, according to a report released Tuesday by iSight Partners, a computer security firm in Dallas.

The targets also included European energy and telecommunications companies and an undisclosed academic organization in the United States, the Internet security report said.

While it is unclear what type of information may have been retrieved, iSight said that the targets of the attacks were often linked to the standoff in Ukraine between Russia and the West.

That included the NATO summit meeting in Wales in early September at which the Russian hackers targeted the Ukrainian government and at least one American organization, the report said.