The Silicon Valley giant has found that tens of thousands of dollars were spent on ads by Russian agents who aimed to spread disinformation across Google’s many products, which include YouTube, as well as advertising associated with Google search, Gmail, and the company’s DoubleClick ad network, the people said, speaking on condition of anonymity to discuss matters that have not been made public. Google runs the world’s largest online advertising business, and YouTube is the world’s largest online video site.

The discovery by Google is also significant because the ads do not appear to be from the same Kremlin-affiliated troll farm that bought ads on Facebook — a sign that the Russian effort to spread disinformation online may be a much broader problem than Silicon Valley companies have unearthed so far.