There appears to be a major outbreak of measles in Pakistan as the World Health Organization revealed that over 100 children have died due to the condition in less than three weeks.
"Some 103 Pakistani children have died from Jan 1 to Jan 19 this year because of the post-measles complications such as pneumonia, post-measles encephalitis and diarrhoea," WHO spokeswoman Maryam Yunus told AFP.
Sixty-three of the cases occurred in the southern province of Sindh, which was hit by severe flooding in 2010, 2011 and 2012.
More than 300 Pakistani children died of measles in 2012, a staggering increase on the previous twelve months and a result of three consecutive years of flooding, officials said.
The WHO said 64 children died of measles in Pakistan in 2011, 28 of them in Sindh. It was not immediately able to provide statistics for earlier years.
The UN body said most of the cases occurred between October and December in northern parts of Sindh, but was unable to provide a breakdown.
The UN body said 33 children died in southwestern Baluchistan province, which is plagued by separatist insurgency and sectarian strife.
The most populous Punjab province reported seven children's deaths. Half of a total of 2,447 cases were reported from Sindh province, of which Karachi is capital.
"It is certainly an alarming situation ...It is an outbreak," said Yunus.
She said WHO and UNICEF provided a combined 4.4 million doses of measles vaccines since last year to target the children in Sindh's flood affected areas.
A senior health ministry official confirmed the WHO figures.
"We can't dispute the figures. Our own teams have similar reports," he said.
"Something must have gone wrong...we are weighing where have we gone wrong," he said.
WHO spokeswoman said a key factor behind more deaths in Sindh was malnourishment, particularly in the flood affected districts.
The ministry official said the number of deaths in January are already "a record high".
Children under nine months are not eligible for the vaccine.