US President Barack Obama has urged Afghan leader Hamid Karzai to "write a new chapter" in governing Afghanistan, after its disputed presidential poll.
Mr Obama said that in a phone call, he had also asked Mr Karzai to intensify efforts to eradicate corruption, BBC reported.
He was speaking after the Afghan president had been declared winner of August's fraud-marred election.
Earlier, poll officials scrapped a planned run-off following the withdrawal of Mr Karzai's challenger.
Mr Obama said he had congratulated Mr Karzai on his re-election.
He described the poll as "messy", but stressed that the final outcome was "in accordance with Afghan law".
Mr Obama said Mr Karzai "assured me that he understood the importance of this moment. But as I indicated to him, the proof is not going to be in words, it's going to be in deeds".
UN chief Ban Ki-moon was among the dignitaries who congratulated Mr Karzai
A number of international figures, including US Senator John Kerry, US Secretary of State Hillary Clinton and UK Prime Minister Gordon Brown, had been involved in persuading Mr Karzai to accept a run-off.
However, Mr Brown on Monday said he welcomed the commission's decision.
A spokesman said the PM had "spoken to President Karzai to congratulate him on his re-election" and the two men had "discussed the importance of the president moving quickly to set out a unifying programme for the future of Afghanistan".
UN Secretary General Ban Ki-moon, who is in Kabul, also congratulated Mr Karzai.
He said Afghanistan's troubled election had been among "the most difficult the United Nations has ever supported".
The BBC's Lyse Doucet in Kabul says there had been intense discussion in recent days as to whether scrapping the second round would be constitutionally legal.
Some observers are saying Mr Karzai's legitimacy is also in question, and ask whether his government can be effective, adds our correspondent.
This would be a particular concern to President Obama as he considers whether to send up to 40,000 more troops to Afghanistan.
Hundreds of thousands of votes were discounted from August's first round, including almost a third of ballots cast for Mr Karzai.
The incumbent's share of the vote was cut to just under the crucial 50% plus one ballot threshold needed for outright victory, following an investigation by the UN-backed Electoral Complaints Commission.
Mr Abdullah had demanded key officials be removed from the IEC, which is widely regarded as pro-Karzai, ahead of any run-off vote.
A Tajik-Pashtun former eye surgeon and ex-foreign minister, Mr Abdullah was judged in the end to have won nearly a third of valid votes cast.