An Iraqi court has sentenced three French citizens to death after they were found guilty of joining Islamic State, a court official said.

Captured in Syria by a US-backed force fighting the jihadists, they are the first French Isis members to receive death sentences in Iraq, where they were transferred for trial.

Named as Kevin Gonot, Leonard Lopez and Salim Machou, they have 30 days to appeal.

Iraq has taken custody of thousands of jihadists repatriated in recent months from neighbouring Syria, where they were caught by the US-backed Syrian Democratic Forces during the battle against Isis.

Iraqi courts have placed hundreds of foreigners on trial, condemning many to life in prison and others to death, although no foreign Isis members have yet been executed.

Those sentenced on Sunday were among 12 French citizens who were caught in Syria and transferred to Iraqi custody in February.

Gonot, who fought for Isis before being arrest in Syria with his mother, wife, and half-brother, has also been sentenced in absentia by a French court to nine years in prison, according to the French Terrorism Analysis Centre (CAT).

Machou was a member of the infamous Tariq ibn Ziyad brigade, “a European foreign terrorist fighter cell” that carried out attacks in Iraq and Syria and planned others in Paris and Brussels, according to US officials.

Lopez, from Paris, travelled with his wife and two children to Isis-held Mosul in northern Iraq before entering Syria, French investigators say.

Iraq declared victory over Isis in late 2017 and began trying foreigners accused of joining the jihadists the following year.

Rights groups including Human Rights Watch have criticised Iraq’s anti-terror trials, which they say often rely on circumstantial evidence or confessions obtained under torture.

Baghdad has offered to try all foreign fighters in SDF custody - estimated at around 1,000 - in exchange for millions of dollars.

Among those sentenced to life in prison are 58-year-old Frenchman Lahcen Ammar Gueboudj and two other French nationals.

Iraq has also tried thousands of its own nationals arrested on home soil for joining Isis, including women, and begun trial proceedings for nearly 900 Iraqis repatriated from Syria.

The country remains in the top five “executioner” nations in the world, according to an Amnesty International report in April.

The number of death sentences issued by Iraqi courts more than quadrupled between 2017 and 2018, to at least 271.

But only 52 were actually carried out in 2018, according to Amnesty, compared with 125 the year before.

Analysts have also warned that prisons in Iraq have in the past acted as “academies” for future jihadists, including the Isis leader Abu Bakr al-Baghdadi.