By Sofia Menchu
GUATEMALA CITY (Reuters) -International election observers will return to Guatemala to monitor a court-ordered review of ballots from the nationwide vote late last month, the Organization of American States (OAS) said on Monday, as tension over the review's fairness mount.
The Washington-based OAS took the unusual step of swiftly returning its observer mission back to Guatemala after its constitutional court called for a review of the election's first round following complaints from the party of the first-place finisher Sandra Torres and allied parties.
Torres challenged the results alleging votes were manipulated, while surprise second-place finisher Bernardo Arevalo denounced the vote review request as lacking legal merit.
"Our fear is that everything is being done to bog down the process," Arevalo told CNN in an interview broadcast later on Monday.
Torres and Arevalo are set to face off in an Aug. 20 runoff, even as the ballot review has raised fresh doubts about the process.
Torres' party does not want the runoff canceled, just a fair review of the first-round vote, according to a statement she posted on Twitter.
A growing list of countries, meanwhile, urged a fair process.
The election to succeed outgoing conservative President Alejandro Giammattei has drawn scrutiny due in part to candidate disqualifications in the lead-up to the June 25 first-round vote, in addition to wide-spread voter anger over corruption.
Germany, Canada, the United States, France, Britain, Sweden, Switzerland, and the OAS itself urged in a separate statement later on Monday that all stakeholders in Guatemala "assure the integrity of the people's vote."
They also called for "free and transparent" action throughout the remainder of the process.
It is not clear how the court-ordered review might affect a second-round vote due in August. The judges have said all complaints must be resolved.
Torres, a former first lady who mounted unsuccessful presidential bids in the past, is expected to face a stiff challenge from Arevalo, the son of a president, who ran on an anti-graft platform.
Some analysts expect Arevalo to do well in the run-off in part due to the unpopularity of Torres in vote-dense Guatemala City.
The court-ordered review will begin on Tuesday morning, the electoral court said in a statement.
"Given the recent resolution of the Constitutional Court ... the mission has decided to deploy again in Guatemala," OAS said in its statement, pledging to help safeguard the will of the voters in Central America's most populous country.