Pakistan freed a hardline Islamist leader on Thursday, a week after removing his name from a terrorism watch list under a deal to end weeks of deadly protests by his followers, the government and his lawyer said.

Saad Hussain Rizvi, the chief of a Sunni militant group - Tehrik-e-Labaik Pakistan (TLP) - was released from a jail in Lahore city, a government spokesman, Hasaan Khawar, told Reuters. His lawyer Muhammad Rizwan confirmed the release.

"By the grace of God, he is a free man now," he said.

The release came two weeks after the government of Prime Minister Imran Khan agreed to free over 2,000 detained members of the TLP movement, lifted a ban on the group and agreed to let it contest elections.

In return, the TLP would shun the politics of violence and withdraw a demand to have France's ambassador expelled over the publication of caricatures of the Prophet Mohammad by a French magazine, negotiators have said.

The TLP took to the streets in mid-October, kicking off weeks of protests and clashes that killed at least seven policemen, injured scores on both sides and blocked the country's busiest highway.

Khan's government had designated the TLP a terrorist group and arrested Rizvi amid similar violent protests earlier this year.

The TLP, which can mobilise thousands of supporters, was born in 2015 out of a protest campaign to seek the release of a police guard who assassinated a provincial governor in 2011 over his calls to reform blasphemy legislation.

It entered politics in 2017 and surprised the political elite by securing more than 2 million votes in the 2018 election.

The next national election is scheduled for 2023, and analysts expect political groups to start gearing up from early next year.