Swat is a part of Malakand, a district in Pakistan's North West Frontier Province (NWFP).
Fazlullah did not specify what measures the group wants the government to implement before a long-term truce can be agreed.
However, he urged Pakistan to enforce sharia in the area and to create "an environment of confidence".
Syed Mohammad Javed, the commissioner of Malakand, said on Saturday that the pro-Taliban fighters had made a "commitment" to a ceasefire.
But Al Jazeera's Imran Khan, reporting from Islamabad, said that the details of the deal were still unclear and that the Taliban might want to act as the "enforcers" of sharia in Swat.
The Taliban were trying to get the government to agree to their key demands - they included the implementation of sharia, the release of all Taliban prisoners," he said.
"But what they also wanted was to control [the implementation of] sharia law within the valley - that would mean a much tougher version of Islamic law than the one Sufi Mohammad had negotiated with the government."
Western powers, as well as many Pakistanis, have been alarmed by the government's offer to implement sharia in Swat in return for a ceasefire deal.
They fear that a ceasefire could result in another sanctuary in Pakistan where al-Qaeda and Taliban fighters could move freely.
They also worry that Taliban fighters elsewhere in the region will be encouraged by the government's move.