Pakistan's government has blocked the social networking website Twitter because of material considered offensive to Islam, according to officials.

Mohammad Yaseen, the chairman of the country's telecommunications authority, said the website was blocked because Twitter refused to remove material related to a competition on Facebook to post images of the Prophet Muhammad.

Many Muslims regard depictions of the prophet, even favourable ones, as blasphemous.

Mr Yaseen said Facebook agreed to address Pakistan's concerns, but officials have not been able to draw the same assurances from Twitter.

Officials from Facebook and Twitter could not immediately be reached for comment.

Pakistan blocked Facebook for around two weeks in 2010 because of a similar competition.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.