Broadcom has come under scrutiny from US lawmakers as it tries to clinch a takeover of rival Qualcomm, with pressure mounting for a US government panel to open an investigation into the potential transaction.

John Cornyn, the second ranking Republican in the Senate, called on the Committee of Foreign Investment in the US to “promptly review” Broadcom’s proposal before a critical March 6 meeting of Qualcomm shareholders, when they will vote on a slate of directors nominated by the Singapore-based group.

In a letter to Treasury secretary Steven Mnuchin on Monday seen by the Financial Times, Mr Cornyn wrote that it would be “deeply concerning” if a foreign company could take control of a US group through a proxy fight without first gaining Cfius approval.