The United States State Department has said it is "closely monitoring" the situation surrounding the June 3 mayoral election in the Moldovan capital, Chisinau.
The June 22 statement came one day after the Moldovan Appeals Court invalidated the election results, saying that both candidates violate election law by appealing to voters via social media on election day.
Pro-European candidate Andrei Nastase won 52.5 percent of the vote in that second-round vote, beating Socialist Party candidate Ion Ceban, who had called for closer relations with Moscow.
The U.S. statement said Washington expected "the Moldovan government to guarantee a transparent court process without political interference."
"If any irregularities are found, we urge all parties to address them in a way that respects the rule of law and democratic principles of government," it said.
The U.S. Embassy in Chisinau had earlier called the invalidation "a troubling development that is...eroding Moldovan citizens' confidence in the democratic process. The European Union also urged the appeals court to uphold the election results in a statement on June 20.