Hundreds of foreign fighters are flowing into Afghanistan to bolster Taliban forces in their fight against the U.S. supported Hamid Karzai government, reports The New York Times [1].

The foreign fighters are not only bolstering the ranks of the insurgency. They are more violent, uncontrollable and extreme than even their locally bred allies, officials on both sides of the Afghan-Pakistan border warn.

They are also helping to change the face of the Taliban from a movement of hard-line Afghan religious students into a loose network that now includes a growing number of foreign militants as well as disgruntled Afghans and drug traffickers.

Foreign fighters are coming from Pakistan, Uzbekistan, Chechnya, various Arab countries and perhaps also Turkey and western China, Afghan and American officials say.

Their growing numbers point to the worsening problem of lawlessness in Pakistan’s tribal areas, which they use as a base to train alongside militants from Al Qaeda who have carried out terrorist attacks in Afghanistan, Pakistan and Europe, according to Western diplomats.

Some Western officials see this influx as a positive development. The Taliban's reliance on foreign fighters to take up mid-level commander duties means coalition forces have been efficient at eliminating indigenous talent.

But Seth Jones of the Rand Corporation says not so fast. Foreign fighters act as a force multiplier and are bringing technical expertise, such as roadside-bomb factories, to Afghanistan, which in the field results in higher Afghan and Western casualty rates.

Another worrisome outgrowth of this militant immigration is an even harsher brand of Islam than associated with local Taliban.

In the southern provinces of Oruzgan, Kandahar and Helmand, Afghan villagers recently described two distinct groups of Taliban fighters. They said “local Taliban” allowed some development projects. But “foreign Taliban” — usually from Pakistan — threatened to kill anyone who cooperated with the Afghan government or foreign aid groups.

Hanif Atmar, the Afghan education minister, said threats from foreign Taliban have closed 40 percent of the schools in southern Afghanistan. He said many local Taliban oppose the practice, but foreign Taliban use brutality and cash to their benefit.