Donald Trump has suggested Google might be working treasonously with China and claimed he would look into the matter.

In a tweet on Tuesday the US president – claiming to quote Fox News – said the tech billionaire Peter Thiel “believes Google should be investigated for treason. He accuses Google of working with the Chinese government.”

He added that the PayPal co-founder – a Trump supporter – was “a great and brilliant guy who knows this subject better than anyone”, and claimed: “The Trump administration will take a look!”

Riva Sciuto, a spokeswoman for Google, said: “As we have said before, we do not work with the Chinese military. We are working with the US government, including the Department of Defense, in many areas including cybersecurity, recruiting and healthcare.”

Trump’s comments came as a House judiciary subcommittee prepared to hold a bipartisan investigation into the market power of Facebook, Google, Amazon and Apple.

Congress will begin two days of hearings on Tuesday on the digital currency planned by Facebook, to be called Libra, starting with the Senate banking committee.

Over the weekend, Thiel said the FBI and CIA should open an investigation into Google.

According to the Axios website, Thiel said Google was “engaged in the seemingly treasonous decision to work with the Chinese military and not with the US military”.