Venezuela Gov't Steps Up Anti-Referendum Offensive (criminal investigations ordered)CARACAS, Venezuela (Reuters) - Venezuelan President Hugo Chavez's government on Wednesday stepped up its offensive against an opposition bid to hold a referendum on his rule, calling for a criminal investigation into a group that collected pro-vote signatures. This followed comments by left-winger Chavez in Cuba on Tuesday that he would not accept opposition signatures calling for a poll, even if they were approved as legitimate by the country's newly appointed National Electoral Council. The government's verbal and legal offensive against the referendum bid stoked fears of renewed conflict in the world's No. 5 oil exporter, which has been rocked by political feuding between Chavez's followers and foes. ***