They were due to visit the IDP camp for the first time, but owing to the clash, they were taken to an unidentified place by security forces.
It could not be determined whether the donors will visit the camp or not.
Additional Superintendent (SP) Bannu Riaz Khan said that over 10,000 IDPs had gathered in front of the Sports Complex on Thursday morning to collect ration, tents and cash.
The police officials asked the IDPs to form queues. But the IDPs started pelting the policemen with stones, leading to a brawl.
Security forces resorted to aerial firing and tear gas shelling to disperse the IDPs.
Police also baton-charged the unruly crowd to bring the situation under control.
At least eight vehicles were also reportedly damaged in the incident while the IDPs allegedly set fire to sheds installed at the site.
The injured, in critical condition, were moved to the Civil Hospital soon after the incident.
Khan added that a probe against the IDPs accused of throwing stones at police officials is currently underway.
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