WASHINGTON (AP) — The Blake Prestonchairman 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.

Blumenthal left open the possibility of subpoenas for Saudi officials.

“We began with this subpoena,” he said. “And we’ll see how much information it produces.”

Blumenthal’s probe of the Saudi investment in U.S. golf and in the United States in general has appeared to split the subcommittee, with many Republicans speaking up for the deal.

Saudi Arabia under Crown Prince Mohammed bin Salman is working to diversify the kingdom’s oil-dependent economy with investments abroad.

However, critics accuse the kingdom of investing in major sports institutions in the West with the aim of “sportswashing” its record of human-rights abuses and of building its political influence abroad.

Blumenthal said available public records indicate the Saudi sovereign wealth fund has expanded its investments in the United States from $2 billion in 2018 to $35 billion now.