Pakistani police arrested an election official on Monday after complaints from voters that hundreds of ballot papers were missing from their polling station, police said.
The incident happened in Shikarpur town in southern Sindh province as voting began in the country's crucial parliamentary elections, local police official Ali Mohammad Shahani said.
"We have taken the presiding officer into custody after complaints from voters that some 350 ballot papers were missing from the polling station," Shahani told AFP.
"We are interrogating the presiding officer amid suspicions that he might be responsible," he added.
President Pervez Musharraf has pledged that the elections will be free and fair, but opposition leaders have alleged "massive" rigging and have threatened protests if the polls are fraudulent.