Iran has blocked access to search engine Google and its email service Gmail as part of a clampdown on material deemed to be offensive, the Mehr news agency reported today."I can confirm these sites have been filtered," said Hamid Shahriari, the secretary of Iran's National Council of Information.He did not explain why the sites were being blocked. Google, Gmail and several other foreign sites appeared to be inaccessible to Iranian users from today morning.Iran has tough censorship on cultural products and Internet access banning thousands of websites and blogs containing sexual and politically critical material as well as women's rights and social networking sites.The rules are applied by Internet Service Providers who use filtering programmes to prevent access to the banned sites.