"Afghanistan has been tarnished by administrative corruption, and I will launch a campaign to clean the government of corruption," he said.
However, he did not make any specific promises to reorganize his administration. Asked if he might replace important officials accused of corruption, he said: "These problems cannot be solved by changing high-ranking officials. We'll review the laws and see what problems are in the law, and we will draft some new laws."
Standing next to Karzai during the news conference was Mohammad Qasim Fahim, a former defense minister who has been accused of drug trafficking, the New York Times reported.
Despite his vow to seek to unify the country, Karzai also declined to answer questions about what role his chief rival for the presidency, Abdullah Abdullah, might play in his government.
Karzai was declared president for a second five-year term by the Afghan election commission after Abdullah dropped out of a run-off election Sunday. The election had been scheduled in order to resolve the months-long political chaos that followed accusations of widespread fraud in the first election in August, and Abdullah said there were no safeguards in place to ensure similar fraud would not take place in the runoff.
President Obama placed a congratulatory call to Karzai, but also asked him to make a much more serious effort to eradicate corruption.
"The truth is not going to be in words, it's going to be in deeds," Mr. Obama told reporters that he told Karzai.
The Times reports that the U.S. is pressing the Afghan government to set up an anticorruption commission. And, the paper reports, some U.S. and European officials would like to see at least a few arrests of "the more blatantly corrupt" officials.
"A couple of high-profile heads on platter would be nice," an anonymous European diplomat told the New York Times.
According to the paper, some potential defendants include Karzai's brother, Ahmed Wali Karzai, who is suspected in the country's illegal opium trade, Gen. Abdul Rashid Dostum, accused of killing thousands of Taliban prisoners of war in the early years of the conflict, and Muhammad Qasim Fahim.
Karzai's relationship with Western leaders has been strained by the widespread suspicion of corruption, as well as by the Taliban insurgency's growing strength.
In his speech, Karzai also held out a hand to Taliban insurgents, asking them to "come home and embrace their land."
But the Taliban leadership snubbed the President's offer.
"We do not attach any value to these offers of peace by Karzai as we know they are empty words," Taliban spokesman Yousuf Ahmadi told the Agence France-Presse.
---- Compiled from wire reports and other media sources