the demonstrations follow a fuel tank explosion that killed at least 29 people in the northern akkar region on sunday. the cause of the blast is unclear, but it occurred as soldiers handed out petrol to residents. a key opposition figure in venezuela has been released from prison two days after the government and opposition representatives met in mexico. freddy guevara was charged with treason and terrorism last month, accusations he denies. the release of political prisoners was one of the demands made by the opposition at the start of talks aimed at ending the country's political crisis. the us government has opened an investigation into tesla's self—driving system. federal regulators are looking into over a dozen crashes involing tesla cars colliding into emergency vehicles. the investigation will cover nearly 800,000 cars made since 2014. 17 people have been injured and one killed in the incidents.