LAHORE, Pakistan (AFP) - A private plane carrying Pakistan's main opposition leader Nawaz Sharif was forced to land on Friday after its windscreen was damaged, officials said.

The plane was flying from the southwestern city of Quetta to a small town in Punjab province.

"Sharif was flying to Hasilpur town, 447 kilometres from Islamabad in a private jet when its windscreen (was) damaged, forcing the pilot to land the plane at the airport in Lahore," civil aviation spokesman Hamid Qaimkhani said.

He said that there were 11 people including Sharif and some of his close aides on board the plane, adding that it had landed safely with no injuries.

Sharif's Pakistan Muslim League (N) spokesman Pervaiz Rasheed told AFP that Sharif was due to address a public meeting in Hasilpur, which has now been postponed.

"We are all safe and nobody got hurt," he said.

Sharif is the frontrunner in Pakistan's election race with just over three weeks before voters go to the polls on May 11. He was first elected prime minister in 1990 but 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 sent into exile in Saudi Arabia in 2000.

He returned in November 2007 just before the February 2008 general election, won by the Pakistan People's Party on a wave of support following the assassination of its leader Benazir Bhutto in December 2007.