Pakistan hanged 12 convicts on Tuesday, the Interior Ministry said, amid a growing uproar over plans to execute a man whose lawyers say was 14 when he was tortured into a confession of killing a child.

Tuesday's hangings, including one man whose lawyers say he was arrested when he was 16, were the largest number of people executed on the same day since an unofficial moratorium on capital punishment was lifted in December.

The death sentence cannot be used against a defendant under the age of 18 when the crime was committed. Testimony obtained by torture is inadmissible. Pakistan says the ages of the defendants whose lawyers say they were juveniles is unclear.

Prime Minister Nawaz Sharif lifted the moratorium on Dec. 17, a day after Pakistani Taliban gunmen attacked a school and killed 134 students and 19 adults. The killings put pressure the government to do more to tackle the Islamist insurgency.

At first, the government said only militants would be executed. But last week it emerged that officials had quietly widened the policy for all prisoners on death row whose appeals had been rejected.

So far, 39 people have been hanged since December. More than 40 are scheduled to hang in the next week, an Interior Ministry spokesman said.

The ministry is reviewing the cases of hundreds more whose appeals have been exhausted. There are more than 8,000 Pakistanis on death row.

Shafqat Hussain is among those due to be executed. Lawyers say he was 14 when he was arrested a decade ago for the kidnap and killing of a child, and that his conviction was based on a confession extracted after nine days of torture.

Interior Minister Chaudhry Nisar Ali Khan had promised an investigation into his age, but Hussain's lawyers say neither they nor the family were contacted.

"It's just a sham, there was no inquiry conducted at all," said Shahab Siddiqui from Justice Project Pakistan, the legal aid group representing Hussain, who is due to hang on Thursday.

The moratorium on executions had been in place since a democratic government took power from a military ruler in 2008.

Human rights groups say convictions in Pakistan are highly unreliable because its antiquated criminal justice system barely functions, torture is common and police are mostly untrained.

Some of Pakistan's allies have criticised the executions.

"Executing a person who committed a crime when he was underage is in violation of international law," said European Union Ambassador Lars-Gunnar Wigemark.

"We do not believe that the death penalty is a deterrent. We are furthermore concerned with possible miscarriages of justice."

The ministry spokesman said of the 12 executed on Tuesday: "They were not only terrorists, they included the other crimes, some of them were murderers and some did other heinous crimes."