Pakistani cleric Muhammad Tahir-ul-Qadri warned the government that his supporters will return to the streets if it doesn't stick to a newly minted deal.
He struck a deal with Pakistan's ruling coalition on Thursday that will give his party some say over the formation of a caretaker government ahead of coming elections.
Mr Qadri's return to Pakistani politics a few weeks ago after years of living in Canada, and his calls for the military be involved in an interim government, sparked speculation that he is backed by the country's army.
He supported a 1999 military coup and praised the military during speeches this week.
A spokesman said that Mr Qadri, who led four days of street protests in Islamabad in a bid to topple the government, will keep pushing for political reforms and a halt to corruption.
As well as giving him a voice in who leads the caretaker administration, the government also agreed to dissolve parliament before the scheduled date of March 16, although it didn't say when.
It said a vote would be held within 90 days of dissolution and electoral reforms would be discussed.
Separately, shops, businesses and schools shut across Karachi after the murder of Manzar Imam, an MP from the Muttahida Qaumi Movement, a coalition partner in the federal government and the dominant political party in the city.
Mr Imam and three of his guards were killed in a drive-by shooting on Thursday.
Overnight violence left five people dead and around 30 wounded.