[Peshawar, Pakistan] Tehrik-e-Taliban Pakistan (TTP), the Pakistan Taliban Movement, has called Afghan President Hamid Karzai's statement about sending troops to fight militants in Pakistan tribal areas “sick” and the “creation of a baffled mind,” and has vowed to resist U.S.-led NATO forces with renewed vigor both in Afghanistan and Pakistan.

Addressing a press conference, Karzai on Sunday threatened to send Afghan troops across the border to fight militants in Pakistan adding, "[they] come and kill Afghanis and kill coalition troops; it precisely gives us the right to do the same."

Talking to The Media Line via phone from an undisclosed location, Moulvi Omar, spokesman for the TTP, rejected outright Karzai’s statement and said, "Karzai is 'sick' and utterly frustrated at Taliban successes in Afghanistan. Taliban has won victory in its resistance against NATO forces, and Karzai's government is confronted with a humiliating defeat."

Karzai, at his press conference, specifically naming Baitullah Mehsud, supreme commander of the TTP, based in South Waziristan Agency, Pakistan, said: "Baitullah Mehsud should know that we will go after him now and hit him in his house."

When asked about Karzai's threat against Mehsud, Moulvi Omar responded that Baitullah was not only the name of an individual but an organization with thousands of supporters.

“He is the leader of our movement and the supreme commander. Let alone hitting him, we will teach a lesson to those who even dare to come close to him with bad intentions," he warned.

Recently, both NATO officials and the Afghanistan government have repeatedly expressed their concern over Taliban infiltration into Afghanistan from Pakistan tribal areas and increasing attacks on allied forces.

In response to a query about Taliban infiltration into Afghanistan, the Taliban spokesman said, it [the Taliban] considered the United States an occupying force in Afghanistan and would never feel reluctant to provide assistance to Taliban groups in Afghanistan, if there were need of any such support.

"Taliban in Afghanistan is resisting U.S.-led forces very well. It has given a very tough time to the occupying forces and as per our religious belief, we will support our brothers [the Taliban] if the need arises," he said.

Omar maintained that on many occasions U.S. forces had violated Pakistan’s borders and killed people inside the tribal areas.

"We are free and committed to the protection of our borders. We are not the slaves of the United States and President Hamid Karzai. We reserve the right to avenge the killing of our people by U.S. forces; we will fight back," he said.

Political observers in Pakistan believe that Karzai’s statement will poison the relationship between the two countries, which are the most important allies in the U.S. war on terror.

Imtiaz Ali, Washington Post correspondent in Peshawar, says that Karzai's statement will place pressure on the Pakistan government to take military action against Taliban insurgents in Pakistan tribal areas instead of signing peace agreements with them.

"For the first time Pakistan responded very strongly to last week’s U.S. air attack on the Pakistan Mohmand Agency and it shows the difference in approach between Pakistan and Afghanistan in curbing terrorism. Karzai’s statement adds a new angle to this and may further complicate the situation in Federally Administered Tribal Areas (FATA) in the future," he added.

Talking to journalists last month in South Waziristan Agency, TTP chief Mehsud also said that Taliban would continue its jihad against U.S. forces inside Afghanistan.

The TTP is an umbrella organization of Pakistan Taliban groups under Mehsud’s leadership.

Pakistan’s newly elected government has negotiated a number of peace agreements with Taliban groups in FATA and the Swat valley of North West Pakistan, which are viewed with suspicion by NATO, Afghanistan and the United States. However, Pakistan insists it is talking only to those who are ready to lay down their arms.