Taliban leader Mullah Mohammad Omar died two years ago in Pakistan and his death was kept secret to avoid demoralisation of Taliban militants, an Afghan intelligence agency said on Wednesday.The Afghan National Directorate of Security (NDS) said Omar died in 2013 in Karachi city."Based on credible information, the NDS has confirmed that Omar died in a mysterious way in a hospital in Karachi two years and four months ago," NDS spokesman Hassib Seddiqi told Xinhua.However, the spokesman said details about Omar's death will be released to the media when appropriate. The comments came amid peace talks between Taliban representatives and Afghan government officials. A wanted man by the US, the one-eyed Omar who has escaped the biggest Washington military manhunt in the region over the past 14 years has several times been reported dead, but no one has seen his coffin.