The incident occurred in Maheshpur village under the Khairabad police station. This was the seventh such death this month, they said.
District administration officials told PTI that the Khairabad area of Sitapur district was the "worst affected".
Some 22 villages of Khairabad block are affected by the dog menace
"A 12-year-old girl, Reena, died today after being attacked by a pack of dogs," Superintendent of Police (SP) Anand Kulkarni told PTI here.
The SP said the administration was tackling the menace and the number of dogs in packs was decreasing.
"Earlier they used to attack in packs of six to eight. Now they are reduced to two or four," he said.
District Magistrate Sheetal Verma, when contacted, told PTI, "Of the 13 deaths due to dog attacks since November 2017, as many as 10 took place in Khairabad police station area."
"Three other cases which took place in the district, were reported from Imlia Sultanpur, Kotwali Sitapur and Taalgaon police station areas," Verma said.
As the problem continued unabated, opposition parties slammed the Yogi Adityanath government by accusing it of ignoring the serious matter.
Congress spokesperson Ashok Singh said, "The incidents of children being killed in dog attacks definitely raises questions on the state government, which has failed to control the menace."
"Furious over the deaths of children due to dog bites, local residents of Khairabad are planning to block the National Highway 24 as a mark of protest. We can understand their pain, agony and sorrow," he said.
Singh said despite such incidents, the state government is yet to wake up from its "deep slumber".
Samajwadi Party spokesperson Sunil Singh Sajan, while taking a jibe at the government said, "What could be more shameful for the state government than dogs killing innocent children."
"The state of affairs in UP is very bad and it seems that there is a jungle raj," he said.
Uttar Pradesh Chief Minister Adityanath had visited Sitapur district on Friday and met family members of the children who had come under attacks from feral dogs.
The chief minister, who had also visited the district hospital to see two injured children, had stressed the need to launch a drive against the dogs which have turned violent.
He had announced a compensation of Rs 2 lakh to each family that had lost a child and Rs 25,000 to every injured child.
Taking cognisance of the repeated incidence of such attacks in Sitapur, the Allahabad High Court has asked the Uttar Pradesh government to spell out the steps being taken to curb the menace of feral dogs.
However, it was felt that the problem may not be limited to Sitapur, but may exist in other parts of the state as well.
The bench comprising justices Vikram Nath and Abdul Moin passed the order on a PIL moved by a local lawyer and granted a month's time to the state government to place its report before the court fixing July 4 as the next date of hearing.
The attacks have generated such fear that school attendance has dipped, the police conduct patrols and men go to work in their orchards and fields armed with rods and axes.
Sitapur's District Inspector of Schools, Devki Singh, said schools in Khairabad have seen a big dip in attendance since May 1. Parents have been issued directions that adults should accompany children to and from school, the officer said.
The areas under the threat of dogs is also under drone camera surveillance, the district magistrate said.
Teams from WWF and Indian Veterinary Research Institute (IVRI), Bareilly, have collected samples such as pug marks, bite-marks and post-mortem reports from the district in recent days.
IVRI director R K Singh said the dogs used to feed on scraps from the slaughter houses in surrounding areas, but were not getting their regular diet now and had turned ferocious.
The state government has been shutting down illegal abattoirs over the past several months.
Veterinarian Anoop Gautam said dogs tend to become more violent when there is a shortage of food. There is also a chance that some nomads may have set their dogs free, he said.
Dinesh Chandra Chaubey, who headed the IVRI team, said detailed tests would be conducted in Hyderabad on samples collected from dogs killed by angry villagers.
On May 1, three children were mauled to death by dogs in villages of Khairabad area after which the district administration called in a team from Mathura to catch the animals, officials said.
Two more children were mauled to death on May 4, while the next day another child was killed by the dogs.