BAGHDAD - The United Nations urged Iraq on Sunday to ratify the international treaty against torture next year amid accusations that torture was used in detention centres under government authority.

Steffan de Mistura, the top U.N. official in Iraq, said ratifying the United Nations Convention Against Torture would send a strong signal from Iraq that democratic countries can "reach stability, fight terrorism" and respect human rights.

"You have done so much in teaching us many things over 5,000 years of culture and civilisations, and we need that lesson from you," he said in a speech at a ceremony in Baghdad marking International Human Rights Day.

A report from the U.N. mission in Iraq covering the human rights situation between January and March said the use of torture and "other inhumane treatment in detention centres under the authority of the Ministry of Interior and the Ministry of Defence continues to be of utmost concern".

The minority Sunni Arab community has also said abuses take place in Iraqi prisons. The majority of prisoners are Sunni Arabs accused of involvement in attacks on the U.S. military and Iraqi security forces.

The Shi'ite-led government has acknowledged some cases of abuse of detainees but said torture was not systematic in Iraqi jails. It has vowed to crack down on human rights violators.

Iraqi Human Rights Minister Wijdan Michael said the government had approved the international anti-torture convention and was awaiting parliament's ratification.

"Implementing this convention will require new legislation and new implementing mechanisms," she said in a speech at the ceremony, also attended by Prime Minister Nuri al-Maliki.

She said the government had invited the U.N. special rapporteur on torture to visit Iraq in early 2008.