WASHINGTON (Reuters) - The U.S. Senate Commerce Committee on Wednesday sent letters to Facebook and Twitter asking the companies to disclose any interactions they have had with presidential candidates Donald Trump and Joe Biden or their campaigns.

The chief executives of the two tech companies along with Alphabet's Google are expected to testify in front of the committee on Oct. 28 about a law that protects internet companies over content posted by users.

The committee did not disclose details for why it wanted access to such information but set a deadline of Oct. 26 for the companies to respond.

(Reporting by Nandita Bose in Washington; editing by Jonathan Oatis)