Activists see the government's claims of blasphemy as a convenient excuse to rein in free-wheeling conversations on the social media site ahead of elections.
The offending tweets, according to Pakistani officials, involved a contest to draw cartoons of the prophet Muhammad. Many Muslims consider any depiction of the prophet to be blasphemy.
Pakistan's newly appointed Minister for Information Technology, Raja Pervez Ashraf, issued a blanket ban on the site inside the country, upping the pressure on Twitter as negotiations continue.
Censorship is nothing new in Pakistan, but often it surrounds matters tied to the country's powerful security establishment. In this case, activists suspect the democratically elected civilian government is using the sensitive topic of blasphemy as cover for constricting the space for political debate ahead of national elections.
"The government is trying to test the waters to see what the response on such censorship is. We foresee more control on access of information, like we have seen in the past, when elections are near," says Shahzad Ahmad, head of Bytes for All, an organization that monitors Internet freedom in Pakistan.