Kabul — A "new species" of terrorist has infiltrated the Afghan capital, posing a growing threat to the country's already-shaky security situation, the head of an international peacekeeping force said Tuesday.

Intelligence reports suggest they are primarily Arabs from Saudi Arabia and Yemen, or come from the Russian republic of Chechnya, said German Lt.-Gen. Goetz Gliemeroth, commander of the International Security Assistance Force.

Many have been caught or killed in operations along the rugged mountainous border region between Pakistan and Afghanistan, where Osama bin Laden and other al Qaeda operatives are believed to be hiding, Gliemeroth said.

"There are clear indications of an increase of terrorist threats both in Kabul and other regions of Afghanistan," the general told his regular monthly news conference.

He cited two recent incidents -- both involving Canadians. The first was a rocket attack on the multinational brigade headquarters in northern Kabul, which injured one civilian Canadian worker in September.

The second was a landmine strike that killed two Canadian soldiers and wounded three others near their base southwest of the city Oct. 2.

They were the first attacks on ISAF troops since four Germans were killed and 29 wounded in a suicide attack on a military bus last June.

"Apart from, if I may say so, the typical terrorist, we've got a new species," Gliemeroth said, adding they are "excellently trained."

"Nowadays, they have even a better improved technique at hand."

Yemen and Saudi Arabia have conducted anti-terrorist raids following repeated calls by the United States to do more to curb Islamic militancy after the Sept. 11, 2001, attacks in the United States.

Gliemeroth said it was unclear if the terrorists were working in tandem with a particular group.

"Whether al Qaeda or special envoys from (renegade warlord) Gulbuddin Hekmatyar or representatives of al Qaeda, I guess it's a mixture," he said.

"Enough terrorists have infiltrated (Kabul) who can potentially cause quite some damage. Against suicide bombs, there is no waterproof protection."

Gliemeroth said terrorist movement into the city is "part of their overall campaign plan." He refused to say what countermeasures had been taken against the terrorists or how many had infiltrated the Afghan capital.

Kabul city police, supported by Canadian and other ISAF troops, arrested Hekmatyar's Kabul commander, Abu Bakr, the day after the Canadians were killed.

Hekmatyar is believed to have ordered rocket and landmine attacks on ISAF forces in and around the city, and the Canadian deputy commander of the 32-nation force, Maj.-Gen. Andrew Leslie, has said Bakr may be behind what he described as a deliberate attack on Canadian troops.

Gliemeroth would not comment on what information, if any, Bakr has yielded.

The 1,950-member Canadian force, which comprises 40 per cent of ISAF, has ordered another 15 armoured vehicles from Canada to address the growing threat.

Afghanistan's hardline Muslim Taliban regime was toppled by a U.S.-led coalition in late 2001 for harbouring members of al Qaeda, the terrorist network blamed for the Sept. 11 attacks in New York and Washington.

ISAF currently is confined to Kabul, but the UN Security Council voted unanimously last week to allow the 31-country force to fan out to key cities in some of Afghanistan's most lawless provinces, where feuding warlords hold power.

Separately, an 11,500-member U.S.-led fighting coalition is in Afghanistan hunting down al Qaeda fugitives and Taliban insurgents.

In recent weeks, the Taliban have stepped up attacks against government troops, aid workers and U.S.-led coalition forces, mainly in southern and eastern Afghanistan.

Afghan officials say the rebels are launching attacks from Pakistan's mountainous frontier regions.

Islamabad says it is doing everything possible to stop the rebels. It has arrested at least 450 al Qaeda suspects, including several bin Laden lieutenants.

The Pakistan army recently launched large-scale raids in the ultra-conservative Waziristan region to crack down on Taliban and al Qaeda insurgents, while coalition forces operated on the Afghan side of the border to trap the insurgents. Pakistan said eight suspected al Qaeda operatives were killed and 18 others captured.