BRUSSELS, Sept. 7 (Xinhua) -- NATO's top commander of operations James Jones on Thursday called on NATO allies to send troop reinforcements, helicopters and transport aircraft to Afghanistan to support the operations in the south of the country.

    Speaking to reporters at NATO's European military headquarters in Casteau, Belgium, after a three-day trip to Afghanistan, Jones said NATO had underestimated the extent of the violence in Afghanistan.

    "While some of it (violence) is predictable, we should recognize we are a little bit surprised at the level of intensity, and that the opposition in some areas is not relying on traditional hit-and-run tactics," Jones said.

    Contrary to expectations, Taliban forces have been engaging NATO troops in fierce gun battles since the alliance moved into the southern region in July.

    Jones called for "modest reinforcements" from the nations contributing to the International Security Assistance Force ISAF), including several hundred additional reserve troops, more helicopters and transport aircraft.

    He said he would urge NATO military chiefs at a meeting in Warsaw on Friday and Saturday to study possible reinforcements and remove restrictions on how and where their country's troops can be used.

    NATO spokesman James Appathurai on Thursday said the alliance had underestimated both Taliban numbers and tactical strength.

    "The Taliban has upgraded its ability to resist in terms of tactics and the numbers it is amassing," he said in Brussels. "This was moving into a territory with which we were unfamiliar."

    Twenty-one NATO soldiers have been killed so far this year but Jones said the number of Taliban guerrillas killed far exceeds that number.

    "In the relatively near future, certainly before the winter, we will see this decisive moment in the region turn in favor of the troops that represent the (Afghan) government," Jones said. Enditem