"Afghanistan is accused with mass corruption. I will try to clean it up," Karzai said.
After three decades of war, Afghanistan faces challenges, he said.
"It is stepping forward towards a more institutional legal order while still struggling against terrorism and the menaces that affect us all. We are aware of difficulties of our governance and the environment in which we live. We'll keep trying to do our best to address the questions ... facing Afghanistan," he said.
In addressing the nation's insecurity, Karzai said he would engage the Taliban.
"The call for peace, the call for security of Afghanistan is one of the main desires of the Afghan people," Karzai said.
"I would also call to the Taliban to ... join the government ... with respect to the Afghan constitution."