Article published on the 2009-03-15 Latest update 2009-03-15 14:58 TU
As police surrounded his home and arrested his supporters, Sharif, who leads the Muslim League (PML-N), claimed that the government had placed him under house arrest.
But ministers from President Asif Ali Zardari's People's Party (PPP) later claimed that Sharif had been placed under police protection because of alleged death threats.
Sharif has vowed to reach the capital Islamabad by Monday for the climax of the third so-called "long march", organised by lawyers and supported by politicians and rights activists.
On Sunday afternoon Sharif defied a ban to lead about 6,000 people through the streets of Lahore, with riot police firing teargas at stone-throwing protesters.
About 1,800 activists have been arrested since Thursday, most of them in Punjab, as the government tries to head off the lawyers' protest, now in its third year.
The campaign has turned into a political standoff between Sharif, who was banned from standing for elected position recently, and Zardari, who came to power after last year's election.
The government is using similar tactics to those used by President Pervez Musharraf before he was toppled by popular unrest, says correspondent Omar Waraich.
"The police in the morning tried to stop Mr Sharif and other people from leaving their homes," he told RFI. "They held the lawyers’ leader under house arrest. When activists gathered outside the High Court scenes turned very violent, very quickly."
Zardari has never been a popular leader, says Waraich, and the news media are now very critical of his government.
"The fact that this government has signed peace deals with militants in Swat but is now targeting democrats in Lahore is going to go down very, very badly," he says.
2009-03-14 15:00 TU