Japan's decision on when to pull its troops from southern Iraq will not be affected by Britain's announcement Monday that it will scale down its military presence in the country, Foreign Minister Taro Aso said Tuesday.

Instead, political developments in Iraq -- particularly the establishment of a legitimate government -- will be a key factor in deciding when to withdraw the Ground Self-Defense Force contingent, Aso said at a news conference.

"(Britain's decision) coming at this time won't affect us," he said.