Both the new cases were reported from the southern port city of Karachi, where several of polio health workers have faced attacks in the recent past.
The first victim was Karachi's Gadap Town resident 10-month-old Omar, who had been vaccinated for the virus once before but still tested positive for the disease, health official Imran Saqib said.
The other victim was 22-month-old baby girl Hajra.
Omar is the fourth victim from this poor locality of Gadap and fourteenth victim from the Sindh province, Dawn reported.
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In 2014 alone, Pakistan's total number of polio cases has reached 160, a sharp increase from 58 cases in 2012 and 93 in 2013.
Earlier this week, 13 new cases of polio were confirmed in a single day.
This year, 113 cases of polio from Federally Administered Tribal Areas (FATA), 27 from Khyber Pakhtunkhwa, 14 from Sindh, two from Punjab and three from Balochistan have been reported so far.
Pakistan, which is already facing travel restrictions imposed by the World Health Organisation, is among the three countries along with Nigeria and Afghanistan where polio virus is endemic.