Sky News:

Pakistan Opposition leader Benazir Bhutto has died after a suicide attack at a political rally.

She was undergoing emergency surgery at a nearby hospital for a suspected neck injury, Sky News sources say.

The explosion went off just after Ms Bhutto left the rally in Rawalpindi, minutes after her speech to thousands of people.

At least 15 people died in the attack in the heart of Pakistan’s military and parliamentary district.

More: The Sun reports that Bhutto’s assassination was carried out by a suicide bomber.

Update (AP): Fox News says she was shot twice in the neck before the bomb went off, so obviously it was a coordinated attack. The first line of this post, from the last time she was attacked, is worth considering. Bhutto herself blamed jihadis for that one but her husband accused the intelligence services of complicity. Given Musharraf’s unpopularity and antipathy to Bhutto, a lot of fingers are going to be pointing at him. God only knows how destabilizing this will prove to be.

Update (AP): Photos are coming in at Getty. Some are graphic so beware.

Update (AP): Right on cue:

“It may have been pellets packed into the suicide bomber’s vest that hit her,” Javed Cheema, an interior ministry spokesman said.

Her supporters at the hospital began chanting “Dog, Musharraf, dog,” referring to Pakistan’s President, Pervez Musharraf. Some of them smashed the glass door at the main entrance of the emergency unit, others burst into tears.

Just how ambitious was the plan here? Take note:

The latest bombing was the second outbreak of political violence in Pakistan today. Earlier, gunmen opened fire on supporters of another former prime minister, Nawaz Sharif, from an office of the party that supports President Musharraf, killing four Sharif supporters, police said.

Mr Sharif was several kilometres away from the shooting and was on his way to Rawalpindi after attending a rally.

Update (AP): The Daily Mail says she was shot by the suicide bomber at close range, and then the bomb went off shortly after.

Update (AP): They tried to kill her yesterday, too: “At her homecoming reception in the port city of Karachi, suicide bombing attacks killed 140 people. Her appearances had drawn large crowds and stringent security checkpoints. At a rally in Peshawar on Wednesday, police stopped a would-be bomber with explosives around his neck. Thursday’s rally was relatively sparsely attended, according to those present, apparently because people feared additional attempts at violence.”

More: CNN has video of the immediate aftermath of the attack.

Update (AP): The Beeb says Rawalpindi is one of the most secure cities in Pakistan thanks to the military garrison there, but of late it’s been infested with jihadis: “In recent weeks, suicide bombers have repeatedly targeted security forces in Rawalpindi, a city near the capital where Musharraf stays and the Pakistan army has its headquarters.”

Update (AP): The first photo at the top here might be the last taken of her.

Update (AP): More blame for Musharraf:

Rehman Malik, Bhutto’s security advisor said: “We repeatedly informed the government to provide her proper security and appropriate equipment including jammers, but they paid no heed to our requests”.

Update (AP): Drudge has a teaser up saying Musharraf was at her bedside. I can’t find any stories to that effect, but Fox News says Nawaz Sharif was there.

Update (AP): The first inevitable warnings of civil war start to trickle in.

Update: The assassination occurred in Rawalpindi, Pakistan, which is near the capital Islamabad.

A quick Google search turns up stories that al Qaeda 9-11 mastermind Khalid Sheikh Mohammed was picked up in a house in that city when he was arrested in March 2003.

Update (AP): Well, who knows. It’s not like they’re going to deny responsibility if asked.

A spokesperson for the al-Qaeda terrorist network has claimed responsibility for the death on Thursday of former Pakistani prime minister Benazir Bhutto.

“We terminated the most precious American asset which vowed to defeat [the] mujahadeen,” Al-Qaeda’s commander and main spokesperson Mustafa Abu Al-Yazid told Adnkronos International (AKI) in a phone call from an unknown location, speaking in faltering English. Al-Yazid is the main al-Qaeda commander in Afghanistan…

Death squads were allegedly constituted for the mission and ultimately one cell comprising a defunct Lashkar-i-Jhangvi’s Punjabi volunteer succeeded in killing Bhutto.

Update: Mark Steyn, a former next-door-neighbor of Bhutto’s, notes the “horrible inevitability” that has occurred today.

Update: Statements from the presidential candidates are starting to come in. Rudy Giuliani’s was the first, followed by Mike Huckabee. Mitt Romney has also issued a statement and video comment.

Update: The rest of the candidates are starting to weigh in. Barack Obama has issued a statement. McCain has as well, but I haven’t found it online yet. Clinton will issue a statement shortly.

Update: USA Today’s blog has a round-up of candidate reactions.

Update: Speaking on CNN a few minutes ago, John McCain noted that there have been 9 attempts on Pervez Musharraf’s life by Islamic militants. There had also been several attempts on Bhutto’s life just in the couple of months since she had returned from exile. It’s always tempting to blame an imperfect non-democratic ruler when there is political violence in his country, but it strikes me as unlikely that Musharraf would have had any involvement in Bhutto’s assassination. He reluctantly allowed her back into the country, both because she was a political threat to him but also because he could not guarantee her safety.

That’s not to say that the ISI is absolved. It’s known to be corrupted by elements that support jihad. But the most obvious beneficiary of Bhutto’s death is al Qaeda and its various allies who create chaos and revel in death in the name of their twisted ambitions. A Pakistan in turmoil is a Pakistan that is weakened as an enemy of jihad.

Update (AP): “I am not afraid. I am ready to die for my country.”

Update (AP): Further to Steyn’s post scoffing at the folly of American diplomats trying to force a shotgun wedding between Musharraf and Bhutto in an increasingly unstable Pakistan, the State Department wonders “what now?”

Update: Bill Richardson reacts to Bhutto’s assassination by insisting that Musharraf must resign. Which would, at least in the short term, add a whole lot of instability to a chaotic situation. Who would replace Musharraf? Richardson doesn’t speculate on that.