Pakistani authorities have placed shipping containers on key roads and highways leading to the capital and suspended cellphone service in Islamabad in an attempt to prevent supporters of imprisoned former Prime Minister Imran Khan from holding a rally seeking his release.

Imran Khan's party leaders have been staging protests, claiming that the Pakistan government should adhere to the constitution.

Authorities in Pakistan sealed off the capital, Islamabad, and blocked cellphone services on Friday to prevent an anti-government rally by supporters of jailed former Prime Minister Imran Khan, officials said.