Tens of thousands of supporters of influential Pakistani cleric, Tahir ul-Qadri, have arrived in Islamabad, demanding electoral reforms at the next general election.
His supporters are calling for an end to corruption, resolve a crippling energy crisis and implement reforms to fix Pakistan's ailing economy.
The cleric, who has also arrived in the capital, has issued a one-day ultimatum for the government to dissolve parliament and provincial assemblies to make way for a caretaker administration.
"Morally, your government and your assemblies have ended," Qadri told his supporters.
"I will give you (the government) a deadline until tomorrow to dissolve the federal parliament and provincial assemblies.
"After that, the people's assembly here will take their own decision."
Qadri told his supporters to camp overnight and advance towards parliament after daybreak on Tuesday.
"Great sons of the democratic revolution, sons, daughters, scholars, trades, government officials, people from all walks of life, stay until I tell you to leave."
He also wants the election commission to disqualify candidates for this year's elections who do not meet a constitutional provision requiring parliamentarians to abide by the tenets of Islam and the Quran.
The convergence of protesters in Islamabad follow a 38 hour march by Qadri from the eastern city of Lahore.
Mobile phone networks have been suspended as part of efforts to shut down much of central Islamabad, to guard against what the government says is a threat of Taliban attacks.
Tahir ul-Qadri only returned to Pakistan last month, after having spent around eight years living in Canada.
Authorities have accused him of trying to delay national polls, which are due in May.