Biometric of power of attorney

I have a power of attorney from abroad for sale of house in karachi. I have been told by the agent/lawyer that I have to take it to the foreign office (ministry of foreign affairs) for biometric. I wanted to ask that can this biometric be done at foreign office in Islamabad or it has to be done in Karachi as the property is in Karachi.
Early response will ne appreciated.
Thanks