With violence steadily increasing in Afghanistan three months before the country's first democratic election, the NATO alliance is planning to reinforce its 6,500-member international peacekeeping force with two units equipped to move quickly to trouble spots.

Each new unit will have about 1,000 soldiers, with one of the units deployed on the north side of the Hindu Kush mountain range and the other to the south, NATO Secretary General Jaap de Hoop Scheffer said in an interview Friday at NATO headquarters here.

"For the election, we'll bring in extra forces to have a quick reaction force . . . so when things go wrong, you can move forces quickly in-theater," de Hoop Scheffer said. He said that Spain had agreed to provide one of the two "rapid reaction" units and that the second would likely come from NATO reserve forces on duty in Europe.

The plan also calls for two additional battalions with about 1,000 members each and a brigade-level headquarters to wait in reserve at bases in Europe and be ready to go quickly if called on.

The additional troops sent to Afghanistan would not amount to a permanent increase in force levels there, de Hoop Scheffer said, but would go strictly to secure the presidential election now set for Oct. 9, staying no more than eight weeks. The rapid reaction forces would return in the spring, when parliamentary elections are scheduled.

At present, the NATO force's operations are limited largely to the capital, Kabul, and five of the country's 32 provinces.

President Hamid Karzai has called on NATO to dramatically increase its troop numbers in Afghanistan before the election and to send soldiers into the most volatile areas of the country. The alliance's limited response has been called insufficient by some officials and commentators in the West.

"I say to the critics, the concept is a mobile concept," de Hoop Scheffer said. "The focus is to be as flexible as we can with those in-theater. So it's not flooding the country with soldiers. I think the Russians found out that's not a viable concept," he said, alluding to the Soviet Union's failed invasion of Afghanistan in the 1980s.

Countries already contributing troops to the contingent, known officially as the International Security Assistance Force, or ISAF, have been reluctant to send more. Germany, currently the leading contributor, has capped its troop level.

The United States has about 20,000 troops in the country, most of them in the south searching for remnants of the former Taliban administration and the al Qaeda network. U.S. forces operate independently of ISAF; the United States contributes no troops to that contingent.

NATO took command of ISAF in August 2003 in the alliance's first military undertaking outside Europe, its traditional area of operation. The move was seen by many member governments as a morale boost for an alliance dispirited by the Bush administration's decision, after Sept. 11, 2001, to go to war in Afghanistan without it. Running ISAF was also seen as a test of whether an alliance founded to confront Soviet armies on the battlefields of Europe could transform itself to meet the new threat of global terrorism.

The force has been hindered by a shortage of equipment and an apparent lack of commitment by many NATO countries. Though ISAF has troops from 36 countries, including a dozen outside the alliance, Canada and Germany continue to provide the bulk of the force. Until recently, it could call on only a few antiquated German helicopters and not a single NATO plane.

Following a NATO summit last month in Istanbul and warnings by the top NATO commander, U.S. Marine Gen. James Jones, that the Afghan mission was at risk of failing, more support has come in. The Dutch, for example, have provided half a dozen Apache attack helicopters. And NATO forces have fanned out slowly into the north, putting civilian-military units known as provincial reconstruction teams in Mazar-e Sharif, Meymaneh, Faizabad, Baghlan and Kunduz.

De Hoop Scheffer said the next step would be to find countries willing to provide troops for the western province of Herat.

Still, he said, NATO has no intention of taking the lead role in securing Afghanistan, nor will it become involved in disarming warlords or suppressing the drug trade. Those tasks, he said, must still fall to Karzai and his Afghan army, which has about 10,000 soldiers.

NATO chief Jaap de Hoop Scheffer said the extra units would be temporary.