Tanzania’s main opposition party said on Friday hundreds of people had been killed in protests over elections this week, as the UN secretary-general called for an investigation into allegations of excessive use of force. The UN human rights office said credible reports indicated at least 10 people were killed in protests in three cities, the first public estimate of any fatalities by an international body since Wednesday’s vote. Story continues below this ad The foreign ministers of Britain, Canada and Norway issued a joint statement expressing concern over the situation and urging the Tanzanian authorities to act with maximum restraint and to respect the right of assembly and of free expression. Speaking to Reuters in some of the government’s first public comments on the unrest, Foreign Affairs Minister Mahmoud Thabit Kombo said the opposition’s death toll was “hugely exaggerated” but that the authorities had not yet tabulated casualties. He denied that security officers had used excessive force. Reuters could not independently verify the casualty figures. Protesters have taken to the streets since Wednesday, angered by …