The leaders of 28 NATO member states are meeting in Chicago to thrash out an exit strategy for the mission in Afghanistan, with timing and financing the main sticking points.

"There will be no rush for the exits," NATO Secretary General Anders Fogh Rasmussen said ahead of the summit. "We will stay committed to our operation in Afghanistan and see it through to a successful end," he added.

In his election campaign, new French President Francois Hollande had pledged to withdraw France's 3,500 combat troops from Afghanistan by year-end, but Rasmussen said Hollande was "very much in accordance" with NATO's plans to gradually hand over security control to Afghan forces and police.

"I feel confident that we will maintain solidarity within our coalition," Rasmussen said.

US President Barack Obama called NATO "the strongest and most successful alliance the world has ever known."

"Our alliance has been the bedrock of our common security, our freedom and our prosperity," the president said. "Though the times may have changed, the fundamental reason for our alliance has not."

Harsh words from Germany

But German Foreign Minister Guido Westerwelle was less diplomatic, warning against "a withdrawal competition motivated by domestic politics" within the alliance that could well exacerbate the terrorist threat in Afghanistan.

German Chancellor Angela Merkel added to the criticism, saying that "we went to Afghanistan together and we want to leave together."

"All those involved should be prudent enough to stick to what was agreed," she insisted.

NATO members had set the date for withdrawal for 2014.

Show me the money

The US is hoping to gain assurances from its allies that they are prepared to stump up $1.3 billion a year (1 billion euros) to help finance the training of Afghan forces and police.

"Our security forces last year cost $6 billion while our national revenue was $1.7 billion," Ashraf Ghani, the head of a commission overseeing the process of passing the baton to the Afghan forces told the Associated Press.

"At the end of the day, it is less expensive to finance the Afghan security forces to do the combat than to deploy our own troops," Rasmussen told broadcaster CNN.

Missile defense shield

NATO members are also set to declare the start of an "interim capability" for the contentious pan-European missile defense shield in Europe. The project had caused ructions with Russia, which will not be represented in Chicago at the highest level by President Vladimir Putin, but by Prime Minister Dmitry Medvedev.

"Missile defense is indispensable. We are faced with real missile threats," Rasmussen said ahead of the summit. The alliance has always said the missiles are not aimed at Russia.

In the first phase, NATO will put a US warship carrying interceptors in the Mediterranean and an early-warning radar system under command of a NATO base in Ramstein in Germany.

'War machine NATO'

Meanwhile, four men were arrested in Chicago ahead of the summit. Police claimed that the men had considered targeting US President Barack Obama's re-election headquarters. According to charge documents released on Saturday, three of the men were caught in the act of making Molotov cocktails, which they had discussed using against the Obama campaign headquarters, police stations, banks and the Chicago mayor's home.

But, defense lawyer Michael Deutsch accused police of setting up his clients in an attempt to frighten peaceful protesters. Another attorney, Kris Hermis said "police have given us minimal information, next to nothing."

Police are bracing themselves for a mass rally and anti-NATO march on Sunday as well as a dozen other protest events.

In Brussels, where NATO has its headquarters, about 100 people staged protests against what they called the "NATO war machine" on Sunday. They carried the flags of around 100 countries not taking part in the summit and decried "NATO's war-like policies and the fact that 28 member states will decide world geostrategic positions," according to the organizers, who were quoted in a report by the Belga news agency.

ng,slk/ipj (Reuters, AFP, AP, dpa)