Visiting Afghan President Hamid Karzai promised Thursday that Japan's financial aid of up to $5 billion will be put to the best possible use.

The Afghan government led by Karzai, who is serving his second term as president, has faced international criticism over corruption and poor governance.

"I guarantee, Mr. prime minister, that the Afghan people will do their best to have this money spent in Afghanistan for the best purposes of developing stability in Afghanistan and where Japan will feel fulfilled of the hard-earned resources that it is spending in Afghanistan," Karzai said in a joint news conference after his talks with Prime Minister Naoto Kan.