The chairman of a Senate investigations subcommittee issued a subpoena Wednesday for documents on Saudi Arabia’s new golf partnership with the PGA Tour, saying the kingdom had to be more transparent about what he said was its $35 billion in investments in the United States.

The move is the latest to challenge Saudi Arabia’s assertion that as a foreign government that enjoys sovereign immunity from many U.S. laws, it is not obliged to provide information on the golf deal.

Sen. Richard Blumenthal’s subpoena comes after the Connecticut Democrat’s unsuccessful requests to the head of Saudi Arabia’s sovereign wealth fund, Yassir al Rumayyan, to testify before Blumenthal’s Senate permanent select investigations subcommittee about the Saudi-PGA golf deal.

The surprise deal, which would join the venerable PGA Tour and a rival Saudi-funded golf start-up, LIV, was announced in June. It overnight gave the Saudi government a major role in one of the main institutions of U.S. sport. Terms of the agreement are still being worked out.

The Saudi sovereign wealth fund, called the Public Investment Fund, or PIF, is controlled by the Saudi government.

“The Saudi’s Public Investment Fund cannot have it both ways: If it wants to engage with the United States commercially, it must be subject to United States law and oversight,” Blumenthal said at a hearing by his subcommittee on Wednesday.

The Saudi Embassy did not immediately respond to a request for comment on the subpoena, which names the Public Investment Fund’s New York-based U.S. subsidiary, USSA International.

This summer’s announcement of the PGA-Saudi golf deal ended a legal battle between the two rivals. As part of that court fight, a federal judge in San Francisco had ruled that Saudi officials would have to sit for depositions and produce documents. Exemptions for commercial activity meant the Saudi claim of sovereign immunity did not apply, the judge said in the ruling, which the Saudis had been fighting at the time the deal was reached.