Mr Mehsud is said to be close to agreeing a peace deal
A top Taleban commander in Pakistan has said his forces stand by a ceasefire agreement with the government, despite recent bomb attacks.
But speaking from his South Waziristan base, Baitullah Mehsud blamed the army for recent attacks on civilians and said he would fight back if necessary.
Mr Mehsud denies reports he ordered the killing of ex-PM Benazir Bhutto.
Meanwhile a police chief and his driver were killed in a roadside bomb attack in the north-western city of Peshawar.
The bomb was apparently detonated by a remote control device close to their vehicle. Two police were also injured.
Hours earlier, another roadside blast killed a civilian and injured three others in Bara, 15km (10 miles) away.
Peshawar is capital of North-West Frontier Province, where pro-Taleban militants often target security forces.
Correspondents say the violence is the first since the formation of a new provincial government.
It was elected on a platform of negotiating with militants, and on Wednesday signed an agreement with pro-Taleban fighters in the troubled Swat valley.
Mr Mehsud is also said to be close to reaching a peace agreement with the authorities, after ordering a ceasefire a month ago.
On Saturday he gave a news conference to a small group of invited journalists, including the BBC's Syed Shoaib Hasan.
Our correspondent says that Mr Mehsud's fighters appeared confident and were in control of the areas that journalists were taken to see.
Mr Mehsud said the onus was on the government and the army to make the peace deal work.
"We have always stood by our word. It is the army who have broken theirs," he said.
"They have attacked civilians in our area, destroyed businesses and schools and killed innocent civilians.
"But we have agreed to the peace and we will stand by it unless the army attacks us first."
He added that his movement was prepared to use suicide bombers if necessary.
He made it clear that his fighters were still opposed to the US. He said he felt "personal enmity" towards America.
South Waziristan has seen many of the heaviest clashes between militants and the security forces in recent years.
Mr Mehsud is said to command about 20,000 pro-Taleban militants.
The previous central government, which supported President Pervez Musharraf, said it had evidence from phone intercepts that Mr Mehsud had organised the killing of Ms Bhutto in Rawalpindi in December.
But Mr Mehsud described the accusations as false, and said he had "nothing against" Ms Bhutto.
Pakistan's new government has offered peace to any militants who renounce violence.
It is attempting to bring to an end a wave of bombings which has killed hundreds of people over the past year.
US officials are cautiously supporting the new government's efforts to reach peace through talks.