Two US senators have offered bipartisan legislation to make it more difficult for Amazon.com and other internet behemoths to make acquisitions.

Senator Amy Klobuchar, a Democrat who chairs the Senate Judiciary Committee’s antitrust group, announced on Friday that she and Republican Tom Cotton have introduced legislation targeting Alphabet’s Google and Facebook.

The bill would make it simpler for the government to prohibit deals that it feels violate antitrust law by requiring firms to demonstrate to a judge that the arrangements are beneficial to competition and hence legal.

A similar bill, introduced by Democratic Representative Hakeem Jeffries and others, has been approved in the House of Representatives Judiciary Committee and awaits a vote by the full House.

Traditionally it is up to the government in antitrust enforcement to show a particular transaction would cause prices to rise or is illegal for other reasons.

“We’re increasingly seeing companies choose to buy their rivals rather than compete,” Klobuchar said in a statement.

“This bipartisan legislation will put an end to those anticompetitive acquisitions by making it more difficult for dominant digital platforms to eliminate their competitors and enhance the platform’s market power.”

Working with others, Klobuchar introduced a bill in October that would bar Big Tech platforms from favoring their products and services.

Other bills introduced seek to rein in the outsized market power of tech firms, including industry leaders like Apple. Thus far none has become law, although one, which would increase resources for antitrust enforcers, passed the Senate.