Nawaz Sharif, seen as the front-runner in Pakistan's election race, said he would not allow militant groups to attack rival India from his country and would work to improve ties with New Delhi if elected.
"If I become the prime minister I will make sure that the Pakistani soil is not used for any such designs against India," Sharif told CNN-IBN in an interview.
Despite recent strains, India and Pakistan's relations have improved after nose-diving in 2008 when gunmen killed 166 people in the Indian city of Mumbai in a three-day rampage that India blamed on a Pakistani militant group.
According to opinion polls, Sharif's Pakistan Muslim League (PML-N) is expected to win Saturday's general election after capitalising on the failure of the outgoing Pakistan People's Party (PPP) to tackle everything from power cuts to a Taliban insurgency.
Cricketer-turned-politician Imran Khan, who has formed his own party, has become one of Pakistan's most popular politicians and could be a major partner in a coalition government, analysts say.
Khan injured his head after falling off a mechanical lift raising him onto a stage at a rally on Tuesday, party and medical officials said.
He fell as the lift was just short of a platform 15 feet (4.5 metres) off the ground in the eastern city of Lahore, witnesses said.
The accident could win Khan some last-minute sympathy votes as he recovers.
Khan has long been viewed as the favourite candidate of the powerful military, which has ruled Pakistan for more than half of its 66-year history.
The liberal PPP has a long history of challenging the military's influence in politics while the military sees the party as corrupt and ineffective.
The poll, which comes after a civilian government has for the first time completed a full-five-year term, has been marred by Taliban violence.
The militant group, which considers the election un-Islamic, has mostly attacked secular-leaning politicians, killing more than 90 people since April.
On Wednesday, four people were killed and 35 wounded in a suicide bombing on a police station in the northwestern district of Bannu, officials in the region said.
Whoever wins the election will inherit enormous problems.
One of them will be managing a difficult relationship with India.
The nuclear-armed neighbours have fought three wars since the partition of British-ruled India in 1947. India has for years accused Pakistan of supporting Muslim militants and sending them in to the Indian part of the divided Kashmir region to fight Indian forces.
Pakistan denies arming the militants saying it only offers moral support to the people of Muslim-majority Kashmir.
Although the two countries began a peace process in 2004, they remain deeply suspicious of each other.
Their antagonism has spilled over into Afghanistan where they compete for influence and where they have tended to support rival Afghan forces.
Strategic ally the United States wants Pakistan and India to bury their differences so Pakistan can focus on helping to stabilise Afghanistan before most NATO combat troops leave by the end of 2014.
Sharif, who was prime minister twice in the 1990s, said it was time to improve ties between New Delhi and Islamabad.
"We have issues of course which need to be resolved and I think I can quote you a lot of examples where rivals or people opposed to each other, countries opposed to each other have resolved much difficult problems than we have," he said.
Sharif, who has been critical of military meddling in civilian affairs, said he would call for a joint investigation of whether Pakistani intelligence agencies played any role in the Mumbai attack.
"I will take up this matter. Certainly this matter will have to be taken up," said Sharif.