"I would suggest that Ahmadinejad think carefully about the obligations to his own people. And he might want to consider looking at the families of those who have been beaten or shot or detained. And that is where I think Ahmadinejad and others need to answer their questions," said Obama.
"If the Iranian government desires the respect of the international community, then it must respect the rights, and heed the will of its own people," he added.
Obama had brushed aside Ahmadinejad's demand for apology on Friday and said he does not take "seriously" his statements.
"I don't think -- I don't take Ahmadinejad's statements seriously about apologies, particularly given the fact that the United States has gone out of its way not to interfere with the election process in Iran," Obama said.
"And I am really not concerned about Mr Ahmadinejad apologising to me," he added.
The Iranian president had sought the apology over the US President's previous comments on Tehran's suppression of political dissent.
