General Abdul Raziq, the Kandahar police commander, was killed outside the provincial governor's office on Thursday, when a bodyguard opened fire on a group of officials as they left a meeting with General Scott Miller, the commander of US and NATO forces in Afghanistan.

Miller was not injured but the regional intelligence agency commander was killed and the provincial governor severely wounded, decimating the leadership of one of the country's most strategically important provinces.

Although nominally a provincial police chief, Raziq was one of the most powerful political figures in Afghanistan and a formidable opponent of the Taliban, with unchallenged authority across the volatile south of the country.

The decision to suspend the vote in Kandahar province was taken over the objections of some officials who warned that any delay would threaten the whole process and hand the Taliban a major propaganda victory.

Saturday's election had been seen as a major test of the government's credibility and ability to organise a nationwide ballot ahead of the more important presidential election next April.

But the shock of Raziq's death meant the people of Kandahar were "morally not ready to vote", said Hafizullah Hashimi, spokesman of the Independent Election Commission.

The Taliban issued a fresh warning not to take part in the election on Friday, telling people to stay at home and saying it would shut down roads and would be "closely monitoring all developments".

The United Nations Assistance Mission in Afghanistan (UNAMA) issued a statement of its own expressing concern at Taliban statements pledging attacks on schools and other buildings used as polling centres.

"UNAMA urges the Taliban to respect and protect civilians and not to threaten them or carry out violence should they engage in their constitutional right to participate in elections," it said.

On top of the mounting security concerns, the elections were already dogged by serious technical and organisational problems, notably around the use of untested biometric voter verification equipment rushed in after allegations of widespread voter fraud.

Thursday's attack underlined how precarious the situation remains in Afghanistan after more than 17 years of war despite preliminary contacts between Taliban and U.S. officials to find a basis for future peace talks.

Miller, who knew Raziq well from his previous tours of duty in Afghanistan, issued a statement saluting a "great friend".

"Afghanistan lost a patriot," he said on Twitter. "The good he did for Afghanistan and the Afghan people cannot be undone."

A disarmingly youthful-looking figure, with a toothy smile belying a fearsome reputation, the 39-year-old Raziq was regularly accused of building a fortune from extracting millions of dollars from traders and businesses.

He was also accused of torturing prisoners and other abuses, which he denied.

Australian Associated Press