The drive is aimed at vaccinating 255,000 children across the district.
Security forces repulse militant attack carried out in Kurram tribal region from across the border in Afghanistan.
The polio workers were being driven to a session in the morning when they came under attack.
Militant organisation Jundullah, a splinter group of Tehreek-i-Taliban Pakistan, claims responsibility for the attack.
Drone fired two missiles on a compound in the Nazyan area of Nangarhar near the Pak-Afghan border.
Khorasani wounded in clash with Afghan security forces.
ATC charges the TNSM chief for treason over his speech against democracy and state at Grassy Ground in Swat in 2009.
Local tribal sources say six unidentified bodies were recovered from Mohmand's Yakaghund area.
Police said gunmen's target was the van driver with whom they had a personal dispute but the girl got injured instead.
Official sources say four militants were killed and one was injured during cross firing with security personnel.
The children were standing on the roof of the well, which had been converted into a gutter, when it collapsed.
Explosion targeted security forces' convoy in Warmagai area of Kurram tribal region.
Two other peace volunteers were also injured in a suspected remote-controlled bomb attack.
Cases of TTP chief Mullah Fazllullah and TNSM chief Sufi Mohammad have been also referred.
Intelligence sources say that four militants were killed in the drone strike in the Nazyan district.
The four-day measles vaccination drive could not commence due to security concerns, officials say.
Drone fired two missiles on a compound and a vehicle in Shawal valley.
Curfew has been imposed in some areas of Dera Ismail Khan as search operation went underway.
She was commended for her meritorious and distinguished services to Pakistan.
Two people killed and two others were injured in an IED blast in Tirah Valley.