A plane returning ex-Prime Minister Benazir Bhutto to Pakistan after eight years of self-imposed exile has taken off from Dubai airport.
Ms Bhutto said her return to Pakistan felt like a 'miracle'
As she headed off for power-sharing talks with President Pervez Musharraf, Ms Bhutto said her homecoming felt like a "miracle", Associated Press reported.
In Karachi, where Ms Bhutto is due to arrive at about 0900 GMT, massive crowds of supporters have gathered.
But there is heavy security amid Islamist assassination threats.
Ms Bhutto was accompanied to Dubai airport by her two daughters, who are remaining in the Gulf state, and has been joined on the flight by about 100 members of her Pakistan People's Party (PPP).
In Karachi, the BBC's Syed Shoaib Hasan says about 200,000 people are lining the 6km (four mile) route from the airport into the city.
Many are dressed in the red, black and green colours of Ms Bhutto's PPP party and there is a carnival atmosphere, with some playing music and food stalls being set up.
However, there were some scuffles, our correspondent says, as a number of people broke through a police cordon to enter the grounds of the airport.
One supporter in the city, Dana Ram, told AFP news agency: "We began walking here 12 days ago, but this is nothing compared with Benazir's sacrifices for us."
Another supporter, a fishmonger called Habibullah, told AP: "She's a blessing for the poor people of Pakistan... Our sister is coming and we're not afraid of anything."
Authorities have tried to persuade Ms Bhutto not to undertake a long procession through Karachi to the tomb of Pakistan's founding father, Mohammed Ali Jinnah, where she plans an address, due to security concerns.
But Ms Bhutto said before leaving that she was undeterred: "I do not believe that any true Muslim will make an attack on me because Islam forbids attacks on women and Muslims know that if they attack a woman they will burn in hell."
06 Oct: Presidential polls held
17 Oct: Supreme Court resumes hearing challenges to Musharraf candidacy
18 Oct: Date ex-PM Benazir Bhutto has set for her homecoming
15 Nov: Parliamentary term ends and general election must be held by mid-January
About 20,000 troops and police have been deployed in the city, Pakistan's largest, to oversee Ms Bhutto's arrival amid threats by Islamist militants to assassinate both her and Gen Musharraf.
Some 2,500 paramilitary troops have been deployed around Karachi airport, according to one security spokesman.
Javed Iqbal Cheema, a Pakistani interior ministry official, said he was confident about security arrangements.
"I'm sure the [provincial] government will take all possible measures to provide foolproof security arrangements which I'm told are already in place," he said.
Gen Musharraf had asked Ms Bhutto to delay her return until the Supreme Court decided whether he was eligible to serve as president for another term.
However, the former prime minister has stuck to her plans.
Gen Musharraf easily won a presidential vote on 6 October after opposition deputies in the national and provincial assemblies - which choose the president - either boycotted or abstained from the vote.
However, the Supreme Court said that he could not be officially declared the winner until it had finished ruling on objections to his candidacy.
Ms Bhutto left the country soon after Gen Musharraf seized power in a coup.
Washington has backed a power-sharing deal with Gen Musharraf which would see Ms Bhutto becoming prime minister.
It has become increasingly concerned over the military's inability to defeat Islamist extremists and Gen Musharraf's rising unpopularity.
Ms Bhutto's negotiators have three main demands:
- The dropping of corruption charges against her
- The repeal of a law banning anyone from being prime minister three times, which affects both her and another ex-PM, Nawaz Sharif
- The surrender of the president's right to dissolve parliament
Gen Musharraf met the first of those demands in an ordinance signed on 5 October but the Supreme Court says it needs to decide if it is legal.
If it rules against it, then Ms Bhutto could face arrest and prosecution on corruption charges dating back several years.
Mr Sharif tried to return to Pakistan on 10 September.
He was arrested by the authorities as he stepped off the plane in Islamabad, charged with money-laundering and immediately put on a flight to Saudi Arabia.