Security, the will of the Iraqi government and cooperation with multinational forces -- most notably the United States -- are factors to be considered when Japan decides whether to extend the Self-Defense Forces humanitarian mission in Iraq, Prime Minister Junichiro Koizumi said Thursday in an interview.

The deployment of 550-member Ground Self-Defense Force troops in southern Iraq expires in mid-December. In a group interview with the media, Koizumi remained mum on whether Tokyo will extend or pull the troops out, but cited the three aforementioned factors in the equation.

"There will be a national referendum (in Iraq over a draft constitution) in October. We have to see (the situation after that), too," Koizumi said.