WASHINGTON: A US congressional hearing scheduled for next week to question the CEOs of Facebook Inc, Amazon.com Inc, Google parent Alphabet Inc and Apple Inc is set to be delayed, according to sources familiar with the matter.

The hearing before the antitrust panel of the House of Representatives Judiciary committee had been set for Monday but will be postponed because Representative John Lewis will be lying in state, the sources said. Civil rights leader Lewis will lie in state in the Capitol from Monday to Wednesday.

No new date has been immediately set for the hearing, which will feature lawmakers questioning Amazon's Jeff Bezos, Facebook's Mark Zuckerberg, Google's Sundar Pichai and Apple's Tim Cook. All four executives are expected to appear virtually.

The hearing was planned to focus on concerns that the companies, which dominate e-retail, social media, search and smartphone software, violate antitrust law in order to maintain or expand their economic clout.

The antitrust subcommittee is expected to release a report within weeks on their investigation into the companies.

The US Justice Department is also probing the big four tech platforms. Facebook and Amazon are also facing inquiries by the Federal Trade Commission, while US states attorneys general are looking at Google and Facebook.

 - Reuters