On Saturday, officials said that pro-Taliban groups had destroyed 61 schools serving around 17,000 children in the valley.
Five girls' schools were set on fire early on Sunday morning in the latest assault.
Pro-Taliban fighters have threatened to launch suicide attacks across the country if the military failed to halt their operations against followers of Maulana Fazlullah, the Pakistan Taliban's leader in Swat who carries a four million rupee ($56,000) bounty on his head.
More than 60 fighters loyal to Fazlullah have now been killed since Tuesday by government security forces, according to officials.
Sunday's clashes erupted after pro-Taliban fighters in the area claimed responsibility for a bomb blast the day before that killed six policemen and three paramilitary soldiers.
Officials said the remote-controlled bomb, which also wounded five policemen, was set off as the group returned to base after a search operation in the Kabal district.
Police said that two suspects had been arrested in connection with Saturday's blast.
"We carried out the bombing which killed the policemen," Muslim Khan, a spokesman for one of the largest pro-Taliban groups in the Swat valley, said in telephone calls to reporters.
He said the fighters were justified in launching such attacks because security forces were killing them.
Hundreds of residents have fled their homes in Swat in the wake of violent clashes, witnesses said.
The mountainous region was a thriving tourist resort until last year, when Fazlullah launched an armed campaign to enforce sharia law in the region.
Under the May peace deal, the government agreed to gradually pull out troops and introduce an Islamic justice system. In exchange, pro-Taliban fighters said they would halt attacks and surrender arms.
"Who killed the innocent people they are bombing and they are shelling from helicopters? It is the Pakistani army," Muslim told Al Jazeera last week.
"I don't want America in my country and I don't want our soldiers to work for America and I want the rules and regulations of Islamic sharia.
"Our government is following rules and regulations of America and we want to change it."