US Defense Secretary Robert Gates (l) with his Canadian counterpart, Peter MacKay, in Cornwallis, Canada, 21 Nov 2008

U.S. Defense Secretary Robert Gates says he wants additional troops in place ahead of Afghanistan's national elections set for next year.

Gates also says the United States wants to move at least four combat brigades each having 3,500 to 5,000 soldiers into Afghanistan between now and early next year, to boost security amid a growing Taliban insurgency.

The U.S. defense secretary made the comments in the city of Cornwallis, Canada Friday, during a two-day meeting with defense leaders from seven other countries, Britain, Australia, Canada, Estonia, Romania, Denmark, and the Netherlands, that also have troops in Afghanistan.

Gates said greater security for Afghan elections are an important goal, and he disputed pessimistic claims that violence is out of control in Afghanistan.

After Friday's meeting, Canadian Defense Minister Peter MacKay told reporters more forces are needed in Afghanistan, but other NATO nations should contribute the additional troops.

Some 70,000 troops under NATO and a U.S.-led coalition are currently serving in Afghanistan.

In the latest violence, authorities say a suicide car bomber killed three civilians, after detonating his explosives at the gate of a military base in southern Zabul province on Friday.

Elsewhere, the U.S. military says Afghan and coalition forces killed four insurgents in fighting north of Kabul on Thursday.

The gunbattle erupted in Kapisa province while Afghan and international troops were searching for militants from the Hizb-e-Islami faction led by Gulbuddin Hekmatyar.

Hekmatyar is a charismatic and experienced guerrilla leader who built his reputation battling Soviet occupation forces in the 1980s, but left Afghanistan in the '90s with the rise of the Taliban.

Meanwhile, a delegation representing the 15 countries of the United Nations Security Council headed to Afghanistan on Friday for a week-long fact-finding mission.

Officials say the U.N. mission will review the humanitarian situation and the status of international pledges to support Afghanistan.