By Brian Ellsworth and Diego Ore CARACAS (Reuters) - Venezuelan opposition leader Henrique Capriles challenged President Nicolas Maduro's narrow election victory before the Supreme Court on Thursday, prolonging what appears to be a futile effort to overturn last month's vote. Capriles refused to accept the results of the April 14 vote for a successor to late socialist leader Hugo Chavez, and called on supporters to take the streets. That led to unruly demonstrations in which the government says nine people died.

Venezuelan President Nicolas Maduro took a swipe at Barack Obama on Saturday, calling him the "grand chief of devils" after the US president declined to recognize his contested re-election. "Coming out of Central America, Obama let loose with a bunch of impertinent remarks, insolent stuff... He is giving an order, and his blessing, for the fascist rightwing to attack Venezuela's democracy," Maduro alleged in an address.

A top election official warned the opposition Saturday against raising "false expectations" over an audit of Venezuela's presidential election, saying it cannot overturn President Nicolas Maduro's win. Opposition candidate Henrique Capriles accepted the expanded audit in lieu of a vote-by-vote recount on the eve of Maduro's swearing-in Friday, helping to ease tensions that had led to eight deaths in post-election protests.

Venezuela's opposition Saturday accused the government of President Nicolas Maduro of engaging in mass arrests of protesters, in a contentious start to his new administration. Maduro, who was sworn in to office on Friday to replace the late Hugo Chavez, said in his inaugural address he was ready for dialogue with the opposition but coupled that with warnings he would take a "hard fist" against those promoting a coup d'etat.