Jawed Ludin, Karzai's spokesman said Thursday that Afghanistan's law allows the president to stay on until the new President is elected, according to press reports.
He made the remarks one day after Karzai's opponents in the presidential race called on him to step down ahead of the Oct. 9 presidential election.
"The president cannot resign before the presidential election as article 161 of the constitution clearly says that he continues in office until the new president assumes charge," Ludin said.
But Karzai's arch rival Abdul Sattar Sirat saw things differently. "The law of the land requires Mr. Karzai to resign ahead of elections if he desires to contest the race," he told reporters. Karzai's rivals maintain that being the incumbent gives Karzai an unfair advantage.
Sirat said that if Karzai refused their demand, his challengers would boycott the election.
The presidential elections, held under U.N. supervision, are the first to be held in Afghanistan since the Taliban regime was driven from power three years ago.