Kurdish-run camps and prisons in northeastern Syria still hold about 56,000 people from dozens of countries, many of them the family members of Islamic State group (IS) suspects, more than five years after the jihadists' territorial defeat in Syria.

While many Western countries refuse to take back their nationals, Baghdad has taken the lead by accelerating repatriations and urging others to follow suit.

The latest group of 505 people is the sixth since the beginning of the year to be repatriated. They left the camp on Wednesday, said Jihan Hanan, Al-Hol's director.

About "153 families arrived yesterday" in Iraq, the Iraqi security official who spoke on condition of anonymity confirmed to AFP.

IS captured nearly a third of Iraq before local forces backed by a US-led coalition defeated them in Iraq in 2017.

In Syria, US-backed Kurdish forces dislodged IS from the last of its Syrian-held territory in 2019.

Al-Hol is located in the semi-autonomous Kurdish region of Syria.

Iraq has intensified its efforts to bring back its nationals amid concerns about the security situation in Syria following the ouster of Bashar al-Assad in December, Iraqi National Security Adviser Qassem al-Araji told AFP last week.

International aid organisations provide services for residents of the Syrian camps, and projects in Iraq have also depended on hundreds of millions of dollars in US assistance in recent years, according to official figures.

Araji said US President Donald Trump's decision to cut foreign aid hinders Baghdad's repatriation efforts.

Al-Hol still holds about 37,000 people, including 14,500 Iraqis, Hanan said.

"More than 4,000 people were repatriated to Iraq since the start of the year," she said. "Under an agreement we reached with the Iraqi government there will be two trip to Iraq each month."