WASHINGTON (AFP) - The United States played down criticism of Afghan President Hamid Karzai ahead of a Paris donors meeting Thursday (today) where he will present a 50-billion-dollar plan to re-build his war-torn nation. Richard Boucher, Assistant Secretary of State for South and Central Asian Affairs, appeared at pains Tuesday to express confidence in Karzai, who has been portrayed as soft on tackling corruption and drug trafficking. "He's the president of the country. We work with him," Boucher told a reporter who asked if he had confidence in Karzai's abilities. When pressed further, Boucher replied: "We have confidence in him. We've done an awful lot with him. We constantly do an awful lot with him ... but ... we're not into rating foreign leaders." The New York Times reported Saturday that US officials were growing increasingly frustrated with Karzai. Unidentified US officials expressed particular frustration over his refusal to arrest drug lords who are running the country's opium trade, which is widely believed to have fuelled the Taliban resurgence, it said. And US officials are saying President George W Bush should use the financial leverage of American aid to Afghanistan to demand that Karzai do more to crack down on corruption, according to the report. Though they admit many problems remain in Afghanistan, Boucher and State Department spokesman Sean McCormack said the country has come a long way since US-led forces ousted the Taliban and its Al-Qaeda allies in 2001. Boucher said the Afghan army was increasingly taking the lead in tackling national security problems. He said the Afghan national solidarity programme was carrying out around 35,000 projects in 25,000 villages nationwide, mostly small-scale ones like bridges, retaining walls, schools, clinics. Regional and local government is also improving, he added. Boucher played up the developments as 80 delegations from around the world prepared to meet in Paris on Thursday to pledge money for Karzai's Afghanistan National Development Strategy. Boucher said he expected the donors to pledge "substantially more" than the 10.5 billion dollars pledged at the London donors conference two years ago, which set out general goals for rebuilding Afghanistan. But his deputy Patrick Moon told AFP that the conference was expected to net a total of 15 billion dollars in pledges. Meanwhile, Germany pledged $653m in development aid to Afghanistan from 2008 to 2010 on Wednesday. "We wanted to continue our support on the highest level," the Foreign Ministry said in a statement announcing the aid pledge. The ministry said the government had already included aid of 140 million euros to Afghanistan in its budget for 2008, but has now decided to match that sum in the next two years. Norway is to pledge $730m to Afghanistan at the donors conference, its foreign minister wrote in a newspaper column Wednesday. "We have decided to raise our aid contribution to 750 million kroner this year," Jonas Gahr Stoere told Aftenposten. "In Paris, I will announce ... that we intend to give the same sum over each of the next five years." Some 80 delegations from around the world will meet on Thursday in the French capital to pledge money for President Hamid Karzai's Afghanistan National Development Strategy. The 50-billion-dollar five-year plan to re-build his war-torn nation aims to substantially surpass the 10.5 billion dollars pledged at the London donors conference two years ago. In February, Oslo announced a 50 per cent increase in aid for 2008, but Stoere said the new package was "not unconditional," with Norway seeking concrete evidence of progress on "development, democracy and human rights." Afghanistan, Sudan and Palestine are the principal beneficiaries of Norwegian aid Oslo being one of the world's largest aid donors, distributing almost one percent of its gross domestic product.