Former Pakistan Prime Minister Benazir Bhutto ended eight years of self-exile on Thursday, making a comeback that could eventually lead to power sharing with President Pervez Musharraf.

Coming home to Karachi to lead her Pakistan People's Party into national elections meant to return her country to civilian rule, a joyful Bhutto set aside fears of assassination by al Qaeda-linked militants who have threatened her return.

"I am thankful to God, I am very happy that I'm back in my country and I was dreaming of this day," a sobbing Bhutto told Reuters as she disembarked an Emirates flight from Dubai.

Dressed in a green shalwar kameez (loose tunic and trousers), her head covered by a white scarf, she passed under the Koran, and kissed the Muslim holy book.

For years Bhutto vowed to return to Pakistan to end military dictatorship, yet she is coming back as a potential ally for General Musharraf, the army chief who took power in a 1999 coup.

Before saying goodbye to her two daughters and husband, Asif Ali Zardari in Dubai, Bhutto described Pakistan as being at a crossroads between democracy and dictatorship.

Musharraf is going through his weakest period, and there is strong speculation he will end up sharing power with Bhutto after national elections due in early January.

The United States is believed to have quietly encouraged their alliance in order to keep nuclear-armed Pakistan pro-Western and committed to fighting al Qaeda and supporting NATO's efforts to stabilize Afghanistan.

While the rest of Pakistan was transfixed by Bhutto's homecoming, Musharraf spent the morning at his army offices in Rawalpindi, with no official engagements scheduled, an aide said.

Bhutto's imminent return has pleased investors. The Karachi Stock Exchange (KSE) benchmark 100-share index struck a life high of 14,802.61 points, up over 1 percent on hopes that her return bodes well for stability and democracy.

More than 100,000 supporters lined the road to the airport and jammed the highway into the city. The crowd was expected to swell once Bhutto left the airport to address a rally.

Some 20,000 security personnel have been deployed to provide protection against threatened suicide bomb attacks by militants.

Intelligence reports suggested at least three jihadi groups linked to al Qaeda and the Taliban were plotting suicide attacks, according to a provincial official.

"She has an agreement with America. We will carry out attacks on Benazir Bhutto as we did on General Pervez Musharraf," Haji Omar, a Taliban commander in the Waziristan tribal region on the Afghan border, told Reuters by satellite telephone.

HOMECOMING RALLY

Bhutto's procession was expected to take several hours edging through crammed roads to a venue close to the tomb of Pakistan's founder, Mohammad Ali Jinnah, for a homecoming rally.

The site for her homecoming address befits a woman whose family history is steeped in Pakistan's torrid past.

Her father, Zulfikar Ali Bhutto, Pakistan's first popularly elected prime minister, was overthrown and hanged, while her two brothers were killed in mysterious circumstances, one gunned down in Karachi, the other found dead in a French Riviera hotel.

She first came to power after military dictator Mohammad Zia-ul-Haq, the general who ousted her father, was killed in a plane crash in 1988. Both her governments were brought down amid allegations of corruption and ineptitude.

Yet no other leader has Bhutto's mass appeal, because of the respect many Pakistanis retain for her father.

Muhammad Ali, a 25-year-old office worker from Larkana, a town in Sindh province where the Bhutto feudal home is located, hitched a lift to Karachi to see a leader idolized by his family.

"I have never seen her in real life before. I love Bhutto and her family, and so do all my relatives," Ali said.

Red, black and green flags of Bhutto's Pakistan People's Party festooned streets and billboards displayed giant images of Bhutto's face.

Musharraf has already granted an amnesty to protect Bhutto from corruption charges brought by the government of Nawaz Sharif, the prime minister he overthrew and later exiled.

But the Supreme Court could still disrupt a rapprochement between Bhutto and Musharraf.

Not only is it challenging Musharraf's right to bestow an amnesty, it is also hearing challenges to the president's right to have stood for re-election while still army chief in a ballot he won easily on October 6.

Musharraf had promised to quit the army and become a civilian leader, meeting another of Bhutto's conditions, if he was given five more years as president. There is speculation that he could invoke emergency powers or martial law if the court blocks him.