More than 100,000 grieving Pakistanis thronged the tomb of slain former premier Benazir Bhutto on Saturday, mourning their beloved leader one year after her assassination. A sea of mourners, some wailing and beating their chests in a wrenching outpouring of emotion, flooded through security checkpoints into the graveyard in rural southern Garhi Khuda Bakhsh for the commemoration. President Asif Ali Zardari, Bhutto's widower, and their three children were to attend the ceremony, due to begin at 9:00 am (0400 GMT) with a reading from the Koran, the Muslim holy book. Bhutto, 54, was assassinated on December 27, 2007 in a gun and suicide attack at a campaign rally in the garrison city of Rawalpindi, just two months after returning to Pakistan from exile to vie for a third term in power. Her shocking death threw the world's only nuclear-armed Islamic nation into chaos, sparking violence and leading to months of political turmoil that ended in September when Zardari claimed the presidency. "In the tradition of a true Bhutto, she faced certain death rather than abandon her principles or the people," Zardari said in a message to the nation to mark the anniversary. "The tyrants and the killers have killed her but they shall never be able to kill her ideas, which drove and inspired a generation to lofty aims." The masses travelled by train, bus, truck, car, bicycle and even on foot to mourn the charismatic, Oxford-educated Bhutto, the first woman to lead a Muslim nation who was hailed in the West as a face of moderation. Tariq Waseem, a 25-year-old student from southwestern Baluchistan province, walked about 400 kilometres (250 miles) over 10 days with about a dozen friends in order to be at Saturday's event. But unlike his friends, he walked barefoot. "These are not painful," he said, pointing with pride at blisters covering his soles. "These are a gift from my martyred leader." Senior local police official Khadim Hussain Rind put the number of mourners at 100,000 late Friday, but said he expected far more would reach the site by Saturday. About 7,000 police and paramilitary rangers joined by ruling party workers and volunteers have fanned out around the tomb to protect Zardari, who has said he too is a target for extremists like those who killed Bhutto. "We do not rule out any threat and we have done all things possible to maintain peace," Rind, one of the point men on security for the event said. A special security wall has been erected around the mausoleum as part of a raft of precautions taken to safeguard Zardari. Closed-circuit cameras have been installed, and mourners were required to pass through metal detectors. All entry and exit routes were cordoned off. One year on, Pakistan's reverence for Bhutto continues unabated -- television programmes about her life have been running for days, and the government has issued a 10-rupee coin and stamps bearing her portrait. Hundreds of vendors did a brisk business selling Bhutto memorabilia -- posters, photographs and recordings of her speeches -- ahead of the ceremony. The government has declared Saturday a national holiday in Bhutto's honour, and events were scheduled in cities nationwide. Bhutto is buried alongside her father Zulfikar Ali Bhutto, a former premier who was hanged in 1979 by the country's military regime. Her brothers Shahnawaz and Murtaza, who died in violent circumstances, are also in the tomb.