UPDATE 2-Venezuela launches criminal investigation into opposition's presidential primary

(Adds details of investigation, context)

By Vivian Sequera and Mayela Armas

CARACAS, Oct 25 (Reuters) - Venezuela's Attorney General Tarek Saab said on Wednesday his office has launched a criminal investigation into the opposition's weekend presidential primary, potentially risking the wrath of the U.S. which has relaxed some sanctions on pledges of a free and fair election.

The government has decried alleged fraud since the Sunday vote, organized without state help and which organizers said attracted more than 2.3 million voters.

The opposition and the primary's winner Maria Corina Machado have insisted repeatedly it was transparent and fair.

Washington has threatened to roll back sanctions relief granted last week on the oil and gas industry and bond trading if President Nicolas Maduro's government fails to lift bans preventing some opposition figures - including Machado - from holding office.

The U.S. State Department did not immediately respond to a request for comment.

The government of Maduro, in power for a decade, and the opposition last week inked an electoral deal in Barbados, agreeing to international observers for the 2024 vote and that each side could choose its candidate according to internal rules.

The deal did not rescind the public office bans for figures like Machado, who was barred for her support of the U.S. sanctions imposed in 2019 after elections which Washington and other Western governments rejected as a sham.

The investigation, requested by lawmaker Jose Brito, will center on accusations of electoral violations, financial crimes and conspiracy, Saab said during a press conference.

The electoral violations stem from the primary being organized without the National Electoral Council, Saab said.

The opposition this month

declined

the council's offer of help and its request to delay the vote until November after the council took several months to respond to the opposition's request for assistance.

Voter rolls for the primary included 2 million people who neither registered nor participated, Saab said, and financing for the primary has not been made public.

"Obviously it is a fraud, who financed this, who is behind it?" Saab said. "The funds are not known. Who provided them?"

His office will interview the organizing commission's president Jesus Maria Casal and vice-president Mildred Camero in the coming days, as well as staff at Sumate, the civil organization which participated in primary organization and whose president Roberto Abdul-Hadi is a reserve member of the commission.

Machado won the contest with 93% of the vote, according to the latest tally of votes released earlier on Wednesday.

The voter figure smashed suffrage expectations, even in some areas traditionally allied with the ruling party.

Voters reported long lines in some polling stations, while others had to be moved or opened late. Some polling places stayed open hours past the original 4 p.m. closing time to ensure those waiting could cast ballots.

(Reporting by Vivian Sequera and Mayela Armas Writing by Julia Symmes Cobb and Natalia Siniawski Editing by Helen Popper and Marguerita Choy)