Russian operatives tried to infiltrate Donald Trump's presidential campaign through his advisers, including foreign policy aide Carter Page, CNN reported Saturday.
CNN said this emerged through FBI intelligence gathering, which triggered an investigation into any possible coordination between Trump campaign operatives and Russian officials.
US officials told the news network that it was unclear whether Page, who is being scrutinized as part of a wider probe over Russian efforts to influence the 2016 elections, was aware that Moscow was trying to use him.
A Russian agent namely would likely have concealed his or her true role or identity while speaking with Page, who himself has vigorously denied any possible collusion with Moscow.
Page gave a speech critical of US policy toward Russia at a top Moscow university last year that caught the FBI's attention and raised concerns that he was maintaining contact with Russian operatives and was being influenced by them.
But Page is just one of several Trump advisers that US and European intelligence revealed had been in touch with Russian officials and other Russian agents frequently and extensively enough to raise suspicions, according to CNN.
Federal prosecutors say that Page met in 2013 with Victor Podobnyy, who turned out to be a Russian operative living in New York. The FBI thus had Page on its radar for at least four years.