A bipartisan group of U.S. lawmakers who are experts in antitrust urged the Federal Trade Commission on Friday to press on with its lawsuit against Facebook, according to a statement from the office of Senator Amy Klobuchar.

In a letter to the new FTC Chair Lina Khan, who took the position last month, Klobuchar and Senator Mike Lee and Representatives David Cicilline and Ken Buck urged the FTC to "pursue enforcement action against Facebook and to consider all available options under the law for ensuring that the commission’s claims receive a full and fair hearing before the court."

Klobuchar and Cicilline are Democrats while Lee and Buck are Republicans. All hold high positions on congressional antitrust panels.

The lawmakers said the behavior alleged in an FTC complaint against Facebook "raised serious competitive concerns." Judge James Boasberg of the U.S. District Court for the District of Columbia dismissed the antitrust complaint, saying the FTC failed to show that Facebook had monopoly power, among other concerns, but said the FTC could file a new complaint by July 29.

The antitrust complaints by the FTC and dozens of states sought to force the social media company to sell Instagram and WhatsApp. Boasberg said the federal complaint was "legally insufficient."