Trucks were set alight in Caracas, Monday, as anti-government demonstrations entered their fourth week.At least 20 people have died since the protests against Venezuelan President Nicolas Maduro began a month ago. Some 10 people have reportedly been killed in the continued clashes between protesters and government forces, and at least 10 are said to have died in looting on April 21.Anti-government protesters are demanding early elections and are convinced Maduro is trying to tighten his