Federal Trade Commission (FTC) Chairman Andrew Ferguson sent a letter to Alphabet CEO Sundar Pichai, accusing Gmail of employing what the FTC calls partisan filtering.

"I understand from recent reports that Gmail's spam filters routinely block messages from Republicans from reaching consumers, while failing to block similar messages sent by Democrats," Ferguson stated in the letter.

A Gmail spokesperson responded that Gmail's spam filters apply equally to everyone, regardless of their political ideology.

Google has previously denied similar claims from Republicans and conservatives.

Republican politicians have long accused major technology companies of discriminating against and suppressing conservative viewpoints, allegations that these companies have consistently denied. In recent months, many tech companies have worked to establish friendly relationships with Republican President Trump, who took office in January.

A Google spokesperson said the company would review the letter and engage "constructively" with it.

The spokesperson explained: "Gmail's spam filters examine various objective signals, such as whether people mark specific emails as spam, or whether particular advertising agencies send large volumes of emails that are typically marked as spam by users. This applies equally to all senders, regardless of political ideology."

In the letter, the FTC Chairman warned Google that non-compliant behavior "could result in FTC investigation and potential enforcement action."

Previously, a U.S. judge dismissed a lawsuit filed by the Republican National Committee alleging that Google intentionally misdirected the party's email messages to users' spam folders.