KANDAHAR, Afghanistan - An overnight rocket strike by international forces killed nine civilians, including at least three children, villagers said Thursday. Local Afghan authorities said they had no reports of civilian deaths.

NATO said the target of the strike was a group of people believed to be planting a bomb and that the alliance was investigating the allegations.

The incident illustrates the confusion and blame that regularly result from night raids and strikes in Afghanistan and threaten U.S.-led efforts to curb the Taliban.

In Kabul, the head of the U.N. mission warned that Afghanistan cannot count on international support indefinitely unless the government tackles corruption and bad governance.

Residents of Korkhashien village drove the bodies to the governor's office in the nearby provincial capital of Lashkar Gah, and Associated Press footage and photos showed at least two children among the dead.

Helmand provincial spokesman Daoud Ahmadi confirmed a strike in Korkhashien, but said eight Taliban militants were killed while hiding out in a compound.

However, President Hamid Karzai's office condemned "the attack on civilians" in a statement. Ahmadi could not be reached to see if his information had changed.

NATO said a rocket fired from the ground hit nine people whom the international coalition believed were planting a bomb. The NATO forces "were not aware of any civilians in the vicinity at the time of the strike," it said in a statement. It said no other people were targeted. NATO said it was investigating the incident but did not give further details.

The NATO force "takes all credible allegations of civilian casualties very seriously and investigates each allegation to determine the facts," Navy Capt. Jane Campbell said in the statement. "If any civilians were injured through our actions, we deeply regret it."

Villager Abdul Rashin said the people were killed while harvesting corn in their fields.

The convoy of vans and station wagons from Korkhashien drove from the governor's office to a central market, where the villagers shouted blame at both Karzai and his international allies.

"Death to Karzai! Death to the foreigners!" they yelled as passers-by looked through the car windows at the blanket-covered corpses. The villagers had propped open the rear doors of the cars to show off the bodies, and a young boy on a bicycle stopped to peer in.

Though NATO forces have retooled their mission to focus on protecting the population -- and have been issued new rules for airstrikes aimed at reducing civilian casualties -- it is often difficult to distinguish militants from civilians in areas where the Taliban live among the people and often grew up in the villages they hide out in.

In eastern Khost province, several hundred people demonstrated Thursday against an overnight raid that killed a resident of Baramkhil village. Walishah Hamat, head of the Mandozayi district government, said the dead man was innocent.

NATO said the man was a militant who was killed when Afghan and international forces were pursuing an insurgent leader who had been recruiting foreign fighters to the area.

More than eight years into the Afghan war, NATO forces are still struggling to fight off the Taliban movement and win the trust of the people they are defending.

NATO forces often struggle in the parallel propaganda war, even though Taliban attacks have killed many more civilians. Late Wednesday, a Taliban rocket killed five civilians when it hit a family's house, said Gov. Jamaldin Bader of Nuristan province.

A fraud-marred presidential election this summer has also weakened support for the Karzai government among its international allies.

Karzai was declared the winner of the presidential race this week after his main challenger, Abdullah Abdullah, withdrew from a runoff that he said could not be free and fair.

Kai Eide, the top UN official in Afghanistan, issued a stern warning to Karzai on Thursday, saying it was imperative that his new administration reform and crack down hard on corruption or risk losing the support of countries that have been providing Afghanistan with funds and with foreign troops to establish security.

"There is a belief among some that the international commitment to Afghanistan will continue whatever happens because of the strategic importance of Afghanistan," Eide said during a news conference in Kabul. "I would like to emphasize that that is not correct. It is the public opinion in donor countries and in troop-contributing countries that decides on the strength of that commitment."

A presidential spokesman argued that foreign donors have also contributed to corruption with the way that lucrative international contracts are awarded.

"Corruption requires closer and more effective co-operation between the government of Afghanistan and the international community," Humayun Hamidzada said. He did not elaborate on the corruption surrounding contracts.

Increasing violence in the country is also threatening the UN mission there. On Thursday, the world body said it was temporarily relocating more than half of its international staff while it looks for safer accommodation for them, following an attack last week on a guesthouse that killed five staffers.

In an initial speech welcoming his re-election, Karzai promised to create an inclusive government and banish the corruption that has undermined his administration. But he did not spell out how he would institute reforms, and he was flanked during his news conference by his two vice-presidents -- both former warlords widely believed to have looted Afghanistan for years.

Eide said: "We can't afford any longer a situation where warlords and power brokers play their own games. We have to have a political landscape here that draws the country in the same direction, which is in the direction of significant reform."

Hamidzada said Karzai is helping unify Afghanistan by bringing these people into government.

"He has brought together Afghans from all walks of life and from all political backgrounds. In order for stability and development to take hold, we must move in the path of inclusivity," he said.

The Afghan Defence Ministry said 17 militants have been killed in three separate clashes in the last 24 hours.