UN Secretary-General Antonio Guterres has expressed regret at the rising death toll in anti-government protests in Iran, and called on the Islamic Republic to respect the rights of peaceful protesters.<br/><br/><br/>Tehran said, 21 people have been killed in clashes across the<br/>country as thousands of people took to the streets. Police have arrested hundreds of demonstrators.<br/>Iran's Supreme leader Ayatollah Ali Khamenei has blamed<br/>the country's enemies for almost six days of deadly unrest that have shaken the conservative country.<br/>