US President Barack Obama today congratulated Hamid Karzai on his re-election as President of Afghanistan. Congratulating Karzai over telephone on his re-election, Obama asked Karzai to improve governance, besides eradicating corruption. Later, Obama said that Karzai assured him that he understood the importance of the time of his re-election. The US President said although the process was messy, he was pleased with the final outcome as it was in accordance with Afghan law.