KABUL, Afghanistan—Afghan President Hamid Karzai says his country's 2014 presidential election will be held on time even though the voting will coincide with the final withdrawal of U.S. and NATO combat troops from Afghanistan.

Karzai told reporters at a news conference on Thursday that he won't stay a day beyond the end of his final term in office because doing so would render his administration an "illegitimate" government.

Karzai had floated the idea of rescheduling the election, arguing that having it at the same time as the troop withdrawal might destabilize the nation.

Opposition groups that have been pushing for an on-time election have expressed concern that Karzai would try to hold on to the presidency beyond the maximum two terms.