Attacks that have continued across Pakistani towns and cities are being blamed on Tehreek e-Taliban, Pakistan's Taliban.
However, the group has issued its first video statement denying involvement in targeting civilians and has blamed external forces for at least two recent blasts.
Azam Tariq, a spokesman of the Tehreek e-Taliban, posted the video statement on YouTube on Monday.
The message refers to a bombing at the Islamic University in Islamabad, which the spokesman said was orchestrated to prepare the ground for a military operation in South Waziristan, a stronghold for Pakistan's Taliban fighters.
He also said his group had no role in the bomb blast in a Peshawar market that killed at least 100 people as well as an attack in Charsada, a town located in Pakistan's North West Frontier Province.
Tariq said Taliban attacks never aimed to target civilians, but that the explosions were linked to Blackwater activities in the country.
Blackwater is a private military and security company founded in the United States.
Kamal Hyder, Al Jazeera's correspondent in Islamabad, said: "Even when those bomb blasts did happen, the Taliban denied they had anything to do it."
He said: "It was surprising to see that it [the video message] came up on the al-Sahab video. That is the Al-Qaeda wing of media publicity."
Blackwater has denied having any contracts in Pakistan.
Hyder added: "There is a growing anger among Pakistanis. If one looks at the type of attacks that have been taking place - indiscriminate attacks – the first thing that came out, even reported by local media, was the blaming of Blackwater and other American agencies.
"The public opinion has turned against the Americans. The video that has appeared today would be trying to capitalise on that."