Pakistan’s defense ministry presented the nation's parliament with inaccurate figures of civilian casualties resulting from U.S. drone attacks, The News International reported on Tuesday, citing top defense ministry officials.

Politicians from opposition parties and human rights activists had slammed the defense ministry’s data, which was released in the last week of October after Prime Minister Nawaz Sharif's return from a trip to the U.S. The critics claimed the casualty total was significantly lower than earlier estimates and that it was wrong and fabricated, triggering a controversy in the Islamic nation, where U.S.-led drone attacks constantly fuel anti-American sentiment.

“It seems the figures changed with the change of circumstances, demands and requirements,” an official commented, according to The News International report.

The defense ministry, in its report to parliament, had said that only 67 civilians were killed in 317 drone strikes between 2008 and 2013, and added that no civilians were killed by a drone strike since January 2012.

These figures contradict both Pakistan’s claims and the assessment of independent agencies such as Amnesty International. On Oct. 18, a United Nations official said Pakistan had reported that about 2,200 people were killed in about 330 drone attacks since 2004, and at least 400 of the victims were civilians, in addition to about 200 others who were “probable non-combatants.”

And, according to a report submitted by authorities from Pakistan’s Federally Administered Tribal Areas, or FATA, to the Peshawar High Court earlier this year, 1,450 civilians were killed in drone attacks during the last five years, The News International report said.

A report in The Nation, citing an Amnesty international report, stated that at least 19 civilians were killed in just two drone strikes in 2012.

The disparity in the data on civilian deaths from drone attacks have raised concerns within Pakistan’s foreign ministry, which fears that reports of a low number could be used by the U.S. to justify its drone strikes in the country, The News International reported.

Defense ministry officials ruled out any conspiracy in understating the number of civilian casualties from drone attacks, the report said, but added that officials, in an apparent contradiction, admitted that internal investigations by the ministry had confirmed that the data were tampered with. Now, a fresh report is expected to be submitted by the defense ministry to the Foreign Office, that would correct the mistakes in the earlier report.

“The report will be presented to the prime minister within the shortest possible time so that Pakistan may again come up with a statement of facts pointing out the mistakes in the reply submitted in parliament,” a senior official said, according to The News International report.