Senator Richard Blumenthal, a Democrat who chairs the Senate Permanent Subcommittee on Investigations, has sent letters to PGA Tour Commissioner Jay Monahan and LIV CEO Greg Norman spelling out the "serious questions regarding the reasons for and terms behind the announced agreement."

Blumenthal said he also wanted to know how any newly formed entity will be structured and operated, including how the PGA Tour intends to preserve its tax-exempt status. He asked for a sweeping set of documents – essentially all communications between LIV and the Tour from October 2021 onwards.

The PGA Tour, the DP World Tour and the rival Saudi-backed LIV circuit, which had been involved in a bitter fight that split the sport, announced an agreement last week to merge and form one unified commercial entity.

"PGA Tour's agreement with (Saudi Arabian Public Investment Fund) regarding LIV Golf raises concerns about the Saudi government's role in influencing this effort and the risks posed by a foreign government entity assuming control over a cherished American institution," Blumenthal wrote on Monday.

The deal could be reviewed by the Committee on Foreign Investment in the US, a Treasury-led committee which assesses mergers to determine if they harm national security.

Treasury Secretary Janet Yellen told CNBC last week that it was not immediately obvious the PGA merger with LIV was a matter of national security.

Last week, senator Ron Wyden, chair of the Senate Finance Committee, explained U.S officials should determine whether the deal would give the Saudis "improper control or access to U.S real estate."