Gen Petraeus formally takes over Afghanistan campaign

US Gen David Petraeus is formally taking command of the 130,000-strong Isaf international force battling insurgents in Afghanistan.

June was the deadliest month for foreign soldiers since the 2001 invasion, with 102 killed, more than half of them Americans.

Gen Petraeus has made clear Nato and the Afghan government must work hand in hand, a BBC correspondent says.

His anti-insurgency strategy in Iraq won praise and he hopes to repeat it.

His predecessor, Gen Stanley McChrystal, was sacked after he and his aides mocked and criticized political leaders in Washington and Kabul.

Gen Petraeus has already warned the Taliban militants are confident and resilient but he has overcome unwinnable situations before, the BBC's Quentin Somerville reports from Kabul.

He arrived in Afghanistan on Friday night and spent Saturday meeting US, Afghan and other officials, delivering a speech to some 1,700 invited guests on the lawn of the US embassy in Kabul.

'Tough mission'

"Civilian and military, Afghan and international, we are part of one team with one mission," Gen Petraeus said.

"On this important endeavour, co-operation is not optional"

Gen Petraeus has already warned that the conflict may become more difficult before major improvements are won.

He and US President Barack Obama have both insisted a change of personnel at the top does not mean a change in strategy.

"This is a tough mission, there is nothing easy about it," the general said on Saturday.

"But working together we can achieve progress and we can achieve our mutual objective."

The gathering on the lawn was upbeat with a rock band playing while dignitaries sat in tents eating popcorn, hamburgers and ice cream, the Associated Press reports.

But the positive tone was dampened by talk of Friday's deadly attack on a house used by an American aid organisation in the northern city of Kunduz, and the accidental killing of two Afghan civilians during a raid in the south, the news agency adds.

US Ambassador to Afghanistan Karl Eikenberry welcomed Gen Petraeus at the embassy gathering, saying: "Welcome aboard. You are welcome at this embassy 24-7."

Mr Eikenberry was one of the US officials criticised by Gen McChrystal in the Rolling Stone article that led to his sacking.

Kandahar challenge

The general met Afghan President Hamid Karzai to discuss corruption among other issues, according to a statement issued by the presidential palace.

Mr Karzai used the meeting to complain about what he said were "baseless" allegations made by Congresswoman Nita Lowey, a Democrat from New York, who suggested Afghan government officials had misused or pocketed donor funds.

One of the general's impending tasks is to step up operations against the Taliban in Kandahar province.

The campaign has been postponed until September.

He has promised to use the same counter-insurgency tactics he used in Iraq and that Gen McChrystal introduced in Afghanistan earlier this year.

Gen Petraeus has also pledged to look at the application of the current rules of engagement.

These are designed to reduce civilian casualties but some US troops believe they put them at too great a risk.