(Reuters) - Malaysian officials investigating a multibillion-dollar corruption scheme linked to a Malaysian state fund and former Prime Minister Najib Razak plan to meet with U.S. officials in Washington, U.S. and Malaysian sources familiar with the plans told Reuters.

FILE PHOTO: A man covers his mouth as he walks past a 1 Malaysia Development Berhad (1MDB) billboard at the funds flagship Tun Razak Exchange development in Kuala Lumpur, Malaysia, February 27, 2015. REUTERS/Olivia Harris/File Photo

The visit, including discussions with U.S. Justice Department officials, could take place before the end of July, the sources said. The plans have not been finalized.

Malaysian officials could include representatives of the Malaysian Anti-Corruption Commission, which is leading local inquiries, two sources familiar with the planning said.

Najib and the fund have denied any wrongdoing.

Officials from the Malaysian attorney general’s office could be part of the Malaysian team, one of the sources said.

A spokeswoman for the Federal Bureau of Investigation, which is participating in U.S. inquiries related to 1MDB, declined to comment.

The planned visit by Malaysian officials to the United States reflects the growing multi-country cooperation that has intensified since Malaysian voters ejected Najib from the Prime Minister’s office in May.

1Malaysia Development Berhad (1MDB), founded by Najib, is at the center of money-laundering investigations in at least six countries, including the United States, Switzerland and Singapore. An estimated $4.5 billion was misappropriated from 1MDB by high-level officials of the fund and their associates, the U.S. Justice Department has alleged.

During an official visit to Kuala Lumpur on Tuesday, Switzerland’s chief federal prosecutor, Michael Lauber, met with recently appointed Malay Attorney General Tommy Thomas to discuss 1MDB, according to a statement by Lauber’s office.

Lauber’s office has been investigating how money obtained by 1MDB and an affiliate which was earmarked for economic development projects allegedly was diverted for what the Swiss prosecutor described as “other purposes, most particularly for the personal enrichment of the persons involved,” according to the statement.

On Monday, the Wall Street Journal reported that Tim Leissner, a former Goldman Sachs Group Inc banker, has been talking with U.S. prosecutors about a possible guilty plea to charges related to the alleged looting of 1MDB. AS lawyer for Leissner declined to comment to the Journal.

Federal prosecutors in Brooklyn, New York, have also been conducting a criminal investigation into 1MDB. Federal prosecutors in Los Angeles have filed civil litigation seeking to recover allegedly looted 1MDB assets.

(The story is refiled to change 1MBD to 1MDB in headline.)