The frontrunner in Pakistan's election race, opposition leader Nawaz Sharif, attracted tens of thousands to a rally at which he promised development and economic revival.
Sharif travelled to the northwestern town of Mansehra, a stronghold of his Pakistan Muslim League-N party, where supporters packed a huge stadium.
Two police officials estimated the crowd at up to 30,000, in contrast to the hundreds who greeted former military ruler Pervez Musharraf on his return to Pakistan Sunday after four years in exile to contest the polls.
Opinion polls are notoriously unreliable in Pakistan, but indicators suggest Sharif is likely to emerge the biggest winner from the general election on May 11, which will mark the country's first democratic transition of power.
The stadium was decorated with large portraits of Sharif and banners reading "Tiger of Pakistan, we love you" and "Welcome prime minister of Pakistan, pride of Pakistan".
The PML-N's election symbol is a tiger and the rally featured a live tiger in a cage.
Many voters are disillusioned with the outgoing Pakistan People's Party (PPP) government, saddled with allegations of corruption and mismanagement. Security and the economy have worsened over the last five years.
Pakistan became a nuclear power in May 1998 during Sharif's second term as prime minister. He was ousted by Musharraf the following year.
"Last time we carried out nuclear explosions. Now we will carry out economic explosions," Sharif told the crowd.
Militant attacks and violence against the Shiite Muslim minority have raised fears about security for the polls in the nation of 180 million.
Sharif ordered a bullet-proof screen around his podium to be removed, a move greeted with loud applause.
But security was extremely tight with police commandos patrolling with AK-47s and a buffer zone ringed with barbed wire around the stage.
As premier, Sharif earned praise for economic reforms and for building a motorway from the northwestern city of Peshawar to Lahore in the east.
He promised that if his party was elected a third time, he would build a motorway from Lahore to Karachi, Pakistan's business capital on the Arabian Sea.
"I am not fond of power, I only want to see my country progressing and my people prosper," he told the crowd.
Sharif first became prime minister in 1990 but was sacked three years later on corruption charges.
He returned to power in 1997 after an election but was ousted in the 1999 coup by Musharraf and was sent into exile in Saudi Arabia in 2000.
He returned in November 2007 just before the February 2008 general election, won by the PPP on a wave of support following the assassination of its leader Benazir Bhutto in December 2007.
Mohammad Afzal, a student aged 18, told AFP he would vote for Sharif.
"Only he can save us from loadshedding (chronic power cuts) and control inflation," Afzal said.
A lawyer on Monday filed an application in the Supreme Court demanding that Musharraf be barred from leaving the country until he stands trial for ordering a siege against a militant mosque in Islamabad in July 2007.
The operation left more than 100 people dead and opened the floodgates to Islamist attacks in Pakistan, which have killed thousands since then.
Musharraf's All Pakistan Muslim League party cancelled a press conference he had been due to give in Karachi. Supporters blamed "scheduling issues" and said it would be held later.
"Our leader came here for the first time after four years and a lot of things need to be decided and finalised," said Muhammad Ali Sherwani, a party official.
He said Musharraf was likely to visit Islamabad on Tuesday and may hold the press conference there.