U.S. Defense Secretary Leon Panetta said Wednesday that the U.S.-led coalition is winning the war in Afghanistan as foreign troops continue to transfer security of the country to Afghan forces ahead of a 2014 deadline.

Panetta told U.S. troops stationed in the eastern Afghan province of Paktika that they face significant challenges in the “very tough conflict.” But he promised to establish a safe, self-governing country where the Taliban and al-Qaida cannot find refuge.

The defense secretary is on a two-day visit to Afghanistan to check on the progress of U.S.-led counterinsurgency efforts, which he says reached a “turning point” this year after a decade of fighting the Taliban.

Panetta is expected to meet later Wednesday with Afghan President Hamid Karzai.

Secretary Panetta has been meeting with U.S. military commanders and Afghan officials to discuss the ongoing transfer of security to Afghan forces.

U.S. President Barack Obama announced earlier this year that 33,000 American troops would withdraw from the country by next October. All international combat troops are set to leave the country by 2014.

The second stage of security transition officially started last month, with Afghan forces set to take charge of six provinces, seven provincial capitals and more than 40 districts. The first stage of the transition began earlier this year.

The transition process has been complicated by worsening U.S. relations with Pakistan, after a NATO air strike last month killed 24 Pakistani soldiers along the country's border with Afghanistan.

Pakistani officials have closed two supply lines into Afghanistan and forced U.S. troops out of a Pakistani airbase following the incident.

The top allied commander in Afghanistan, General John Allen, said Tuesday he was making efforts at resolving the issue during his recent talks with Pakistani officials.

Panetta again said on Tuesday that the U.S. believes healthy U.S.-Pakistan relations are vital for ending the conflict in Afghanistan.

In the latest violence, Afghan officials say a local government official was killed after his vehicle struck a roadside bomb in the restive southern province of Helmand.

U.S. officials reported in October that the number of Taliban attacks in Afghanistan decreased for the first time in five years. However, the United Nations said earlier this year the number of civilians killed went up by 15 percent in the first half of 2011, with nearly 1,500 deaths due mostly to insurgent attacks.