The widower of assassinated former Pakistani PM Benazir Bhutto has told a rally of her party's supporters to protest if coming polls are rigged.
Asif Ali Zardari spoke from behind a screen of bullet-proof glass
Asif Ali Zardari, who succeeded his wife as head of the Pakistan People's Party (PPP), said activists were ready to "besiege" polling stations.
Mr Zardari was addressing a crowd of thousands in the politically pivotal province of Punjab.
President Pervez Musharraf has insisted the elections will be free and fair.
"Despite all the insinuation and apprehensions, the elections will be free, fair, transparent and peaceful," Mr Musharraf told state television.
He also cautioned his political opponents against possible street protests.
"If people think they can come on streets after the elections, nothing of that sort will be allowed," he said.
As president, Mr Musharraf is not contesting the parliamentary elections on 18 February.
However, the former military leader could face a serious challenge to his authority if the vote produces a hostile parliament packed with his opponents.
The election is regarded as a vital step in Pakistan's transition from military to civilian rule but many observers have warned it is unlikely to be free or fair.
Thousands of PPP supporters attended Thursday's rally in the city of Faisalabad in Punjab.
PPP supporters hope to avenge Ms Bhutto's death at the ballot box
"I came to Punjab to save Pakistan, Bhutto's Pakistan," Mr Zardari told the crowd from behind a screen of bullet-proof glass.
He also said the party would not be intimidated by attempts to rig the elections.
"We will besiege the polling stations till the election results are announced in the presence of the party's polling agents," he said.
In an earlier interview with the AFP news agency, Mr Zardari said his party was prepared to protest if it was unhappy with the conduct of the polls.
"We will call for all the political forces to get together, and together we shall decide how to take the people to the streets, how to do political agitation enough to get our point of view across," he was quoted as saying.
Security was tight, with police snipers positioned on rooftops overlooking the gathering.
BBC poll findings are gloomy news for Mr Musharraf and his allies
The PPP has its base in the southern province of Sindh but must fare strongly in Punjab province if it is to lead any future government.
Punjab is home to more than half of all Pakistanis and the election this year is likely to produce a bitter three-way contest between the PPP and the two opposing wings of the Pakistan Muslim League, PML-Q and PML-N.
At a PML-N rally on Thursday, the party's leader and a former PM, Nawaz Sharif, accused Mr Musharraf of trying to buy votes.
"In order to survive, he has to rig the election. He knows that," he told a crowd of supporters in the northern town of Kahuta.
Musharraf 'less popular'
Meanwhile, a BBC World Service poll has found a majority of Pakistanis believe the country will be more stable if Mr Musharraf resigns as president.
The survey of more than 1,400 people across Pakistan suggested support for Mr Musharraf has fallen dramatically.
The respondents were divided about whether the 18 February elections would be free and fair.
A nationally representative sample of 1,476 Pakistani adults were polled from 27 to 28 January 2008 on behalf of BBC Urdu.
A spokesman for President Musharraf told the BBC the poll did not represent public opinion.
He specifically dismissed the finding that almost half of those surveyed did not regard Mr Musharraf's re-election to the presidency in November as valid.
"It is something that doesn't stand to reason," Rashid Qureshi said.
Recent events have helped change Pakistan's political landscape, the BBC's Jill McGivering says.
Most dramatically, the murder of Ms Bhutto on 27 December has created a wave of sympathy for the opposition.
In contrast, there has been a backlash against President Musharraf and his government since Ms Bhutto's death.
Mr Musharraf is also increasingly unpopular because of a faltering campaign against pro-Taleban militants in the country's north-east and a clampdown on the judiciary.