BAGHDAD: The arrest of a prominent political commentator has revived bad memories in Iraq, where laws inherited from Saddam Hussein's regime are still being used to silence critics 18 years after his ouster.

Late Thursday night, Ibrahim al-Sumeidi was arrested at his house after he criticised politicians over revisions to a law on the Supreme Court in a private online conversation later published on social media.

After being interrogated, he was released on Sunday by a Baghdad court.

But he faces trial for defamation, "insulting" state institutions and spreading "false or biased information".

The charges are based on a penal code dating back to 1969, shortly after the Baath party coup which eventually brought Saddam to power.

The United States, which led a coalition to oust the dictator in 2003 with the stated aim of bringing democracy to Iraq, supervised the re-writing of the country's constitution.

But 18 years later, the penal code remains.

"Arrest warrants are being issued against journalists, activists and commentators in Iraq based on laws dating back more than five decades, some of which carry sentences of life imprisonment or even death," says the country's Journalistic Freedoms Observatory.

The organisation's head, Ziad Ajeili, called for the repeal of "laws passed down from former totalitarian systems and which conflict with the post-2003 Iraqi constitution".

Sumeidi's arrest comes as activists face a string of other threats.