Violence continues to escalate in Afghanistan. On Wednesday, a provincial governor escaped an apparent assassination attempt outside his office in the Northeast. A day earlier, suspected Taleban gunmen killed a senior judge outside a mosque in Western Afghanistan.

The latest attacks are fueling concerns that the Taleban has regrouped and is gaining ground throughout the country.

In Southern Afghanistan, officials say many militants no longer bother trying to keep their presence hidden, and openly challenge local authorities.

In the capital, Kabul, NATO officials warn of increased suicide bombings to come, after suspected Taleban insurgents launched four suicide attacks in 48 hours.

But Afghan and U.S. officials maintain that the Taleban's latest offensive is a sign of desperation, not strength.

"Anytime you are taking the fight to the enemy, which is what we are doing all over Afghanistan - we are putting them on the defensive, and anytime you do that, one of the consequences is going to be increased enemy attempts to push us back," said the U.S. military spokeswoman, Lieutenant Tamara Lawrence.

The latest attack occurred in the capital of Nangarhar province, about 75 kilometers east of Kabul.

Officials say the provincial governor, Gul Agha Sherzai, escaped injury after a bomb exploded outside his offices.

The bomb was hidden inside an army vehicle, and was reportedly meant to explode as Sherzai entered the building. But the governor apparently went to work earlier than normal and was inside when the bomb exploded.

Nobody was hurt, and Sherzai said three suspects had been arrested.

But in Farah province in Western Afghanistan, suspected Taleban gunmen succeeded in killing a senior judge late Tuesday as he left a mosque.

Witnesses say at least two militants on motorbikes opened fire as civil court Judge Sheikh Mohammed left an evening prayer service in the provincial capital.

The Taleban's growth coincides with American plans to withdraw thousands of troops from the southern provinces, where the militants are considered most powerful.

A U.S.-led military coalition ousted the hard-line Islamic group in 2001, after its leaders refused to hand over terrorist leader Osama bin Laden.

Washington says it now plans on reducing U.S. troop strength in Afghanistan, from about 19,000 to 16,000 by the end of this year.

The U.S. forces will be replaced in the South by a beefed-up NATO peacekeeping mission, which will assume overall command for security in that region.

Local Afghan officials are questioning NATO's ability to beat back the Islamist militants in the region.

Lieutenant Lawrence says U.S. forces will still play a key role in the country's overall defense, focusing primarily on counter-terrorism operations.