A supporter of former Pakistan prime minister Nawaz Sharif casts his vote at a polling station in Lahore.
Pakistanis turned out to vote in elections on Saturday, defying deadly Taliban attacks to take part in an historic democratic transition for the nuclear-armed state.
A bomb attack claimed by the Taliban killed 11 people in Karachi while gunmen shot dead six in the restive south-west, but the election commission estimated turnout could rise up to 60% as voters thronged the polls in major cities.
The main issues are the tanking economy, an appalling energy crisis that causes power cuts of up to 20 hours a day, the alliance in the US-led war on Islamist militants, chronic corruption and the dire need for development.
More than 86-million people are eligible to vote at 70 000 polling stations for the 342-member national assembly and four provincial assemblies in Khyber Pakhtunkhwa, Punjab, Sindh and Baluchistan.
The vote marks the first time that an elected civilian administration has completed a full term and handed power to another through the ballot box in a country where there have been three military coups and four military rulers.
'Long live the lion'
The front-runner is ex-prime minister Nawaz Sharif, head of the centre-right Pakistan Muslim League-N (PML-N), but much of the campaign has been electrified by cricket star Imran Khan with promises of reform and an end to corruption.
Sharif arrived to vote in Lahore, driven in a bulletproof vehicle and greeted to roars of "long live the lion" from his supporters using his nickname.
"I am confident that tonight we will start receiving good news from across the country," Sharif told reporters after casting his vote.
Long queues formed outside polling stations in Pakistan's main cities where people spoke enthusiastically about exercising their democratic right and voting for change, although some people expressed nervousness about security.
"People have been up all night, actually I haven't slept, a lot of my friends haven't slept. People just wanted to come out and do this, because we never had this chance," said Natasha Ejaz, a singer, in Islamabad.
In Pakistan's financial hub Karachi, supporters of rival political parties accused each other of rigging, and the Taliban targeted a candidate for the Awami National Party (ANP), one of the secular parties in the outgoing government.
Rigging allegations
The target, Amanullah Mehsud, escaped unhurt, police said, but 11 other people were killed, including a small child, and around 40 people wounded.
Karachi was the focus of rigging allegations with Islamist party Jamaat-e-Islami boycotting the poll in the city after accusing the Muttahida Qaumi Movement (MQM), which controls Karachi, of vote fraud and violence.
The MQM denied the allegations.
The election commission also raised concerns about threats to its staff in the port city, which it says has prevented them from performing their duties.
The commission announced it would extend voting hours from 5pm to 8pm in one of the city's districts to compensate for a delay in opening polling booths.
Officials said turnout was around 30% by midday and was expected to rise to 60% before the polls close, which would eclipse the 44% seen in the 2008 polls.
More than 600 000 security personnel have deployed to protect the vote and around half of all polling stations have been declared at risk of attack, many of them in insurgency-torn parts of Baluchistan and the north-west.
Pakistan also sealed its border with Afghanistan and Iran to boost security.
Pre-election killings stand at 127 people
Pre-election violence killed at least 127 people, according to an Agence France-Presse tally, and the campaign has been called the bloodiest in the country's history.
In the north-west, the part of the country most troubled by an almost seven-year Taliban insurgency, bombs wounded 12 people – eight near a women's polling station in Peshawar and four others near a polling station in Mardan district.
In North Waziristan, a notorious Taliban stronghold, mosque loudspeakers announced that no woman would be allowed to leave their home to vote, according to local residents. Women's turnout is traditionally low in conservative areas.
The PML-N and Pakistan People's Party (PPP) have dominated politics for decades, led by two of the richest families in the country, the Sharifs and the Bhuttos.
The outgoing centre-left PPP has run a lacklustre and rudderless campaign, with its chairperson Bilawal Bhutto Zardari too young to run and largely hidden from public view due to Taliban threats.
But Khan has sought to galvanise a young, urban middle class with promises of sweeping change.
Sharif earmarked as the most probable winner
With no reliable polling data, Sharif has been earmarked the most probable winner but if Khan's Pakistan Tehreek-e-Insaf party do well enough to become a formidable opposition, there are concerns that the emergent coalition will be weak and possibly short lived.
Sharif served as prime minister from 1990-1993, when he was sacked for corruption, and from 1997-1999, when he was deposed by the military, although his family say he is a changed man who will this time govern more successfully. – AFP