The officials said the three Iraqis were executed in Nasiriyah prison in Dhi Qar province, the only detention centre in the country that carries out capital punishment.

A 2005 law carries the death penalty for anyone convicted of "terrorism," which can include membership of an extremist group, even if the convict is not found guilty of specific acts.

Since declaring the Islamic State group defeated in late 2017, Iraq has condemned hundreds of its own citizens to death for membership of the jihadist group.

But only a small proportion of the sentences have been carried out, as they must be approved by the country's president -- currently Barham Saleh, who is known to be against capital punishment on a personal level.

Last month, Iraqi authorities revealed that they had more than 340 execution orders "for terrorism or criminal acts" that were ready to be carried out.

A presidential source told AFP at the time that a majority of those approvals dated back to before Saleh became president.

Wednesday's group execution was the third known execution this year alone.

The first, which saw three people hanged in late January, came just days after a twin suicide attack on Baghdad that killed at least 32 people and was claimed by IS.

Despite Saleh's moderating influence, Iraq in 2019 carried out the fourth highest number of executions among nations worldwide, after China, Iran and Saudi Arabia, according to Amnesty International.

Although there are no public records for 2020, judicial sources told AFP at least 30 executions took place last year.

In 2021, at least 11 people have been hanged already, according to local officials in Nasiriyah.