Pakistan's former military ruler Pervez Musharraf returned home on Sunday after more than four years in exile, defying a Taliban death threat to contest historic general elections.The 69-year-old ex-dictator says he is prepared to risk any danger to stand for election on May 11, in what will be the first democratic transition of power in the history of a nuclear-armed country dominated by periods of military rule.He seized power in a bloodless coup as army chief in 1999 and left the country after stepping down in August 2008, when Asif Ali Zardari was elected president after the murder of his wife, former prime minister Benazir Bhutto.Musharraf's Emirates flight from Dubai landed at around 12:45 pm (0745 GMT) after a journey that saw his official Facebook and Twitter accounts provide a running commentary, posting messages and photographs of him on board."Settled in my seat on the plane to begin my journey home. Pakistan First!" said one message posted on the @P_Musharraf Twitter account, with a picture of him wearing an off-white, traditional shalwa kameez outfit.Some of his supporters on the flight shouted "long live Musharraf", annoying other people among the regular passengers, according to an AFP reporter on board.Musharraf, who has been granted protective bail to lift the threat of immediate arrest on his return to Pakistan, told reporters before leaving for Karachi that he was "not feeling nervous" but admitted to some concerns."I am feeling concerned about the unknown... there are a lot of unknown factors of terrorism and extremism, unknown factors of legal issue, unknown factors of how much I will be able to perform (in the elections)," he said.He was forced to scrap plans to address a public rally at the Karachi tomb of Pakistan's founding father Mohammad Ali Jinnah because of security fears and will instead address supporters at the heavily secured airport.Police withdrew permission for the downtown rally after the Pakistani Taliban threatened to dispatch a squad of suicide bombers to assassinate Musharraf. In one of the legal cases that has long ensnared Musharraf, Benazir Bhutto was assassinated when he was running the country in December 2007, three months after she returned to Pakistan from her own self-imposed exile.Karachi, a city of 18 million, is already in the throes of record political and ethnic violence. On March 3, a huge car bomb killed 50 people in a mainly Shiite Muslim area of the city, the worst single attack in the city for years.Just hours before Musharraf's homecoming, a suicide bomber killed 17 Pakistani soldiers by ramming a water tanker packed with explosives into a checkpoint in the tribal district of North Waziristan.There was no immediate claim of responsibility, but North Waziristan is a known stronghold of the Taliban and operatives linked to Al-Qaeda. Pakistani troops have been fighting homegrown insurgents in the tribal belt for years.As ruler, Musharraf escaped three Al-Qaeda assassination attempts. He became a prominent target for extremists after making Pakistan a key US ally in the "war on terror" after the 9/11 attacks.In July 2007, he ordered troops to storm a radical mosque in Islamabad. The operation left more than 100 people dead and opened the floodgates to Islamist attacks in Pakistan, which have killed thousands since then.Meanwhile Bhutto's son Bilawal Bhutto Zardari, who is chairman of the Pakistan People's Party, has accused Musharraf of her murder.In 2010 a UN report said Bhutto's death could have been prevented and accused Musharraf's government of failing to provide her with adequate protection. His administration blamed the assassination on the Pakistani Taliban.Musharraf is wanted by the courts over Bhutto's death, the 2006 death of Akbar Bugti, a Baluch rebel leader in the southwest, and for the 2007 sacking and illegal arrest of judges.Analysts say there is a real danger to his life, which outweighs his political future in a country where he is likely to win no more than a couple of seats for his All Pakistan Muslim League party.