Iran should immediately halt the execution of children, the U.N.'s top human rights official said Monday.

Louise Arbour, the U.N. high commissioner for human rights, said she met with Iranian officials during a visit to Tehran earlier this month and urged them to impose a moratorium on the execution of minors.

"Even if the legislation in the books appears to permit the imposition of the death penalty on minors ... it would be imperative that they not be executed," she told journalists in Geneva.

Iran is one of the few countries in the world that executes minors, in violation of the U.N. Convention on the Rights of the Child.

On Sunday Iranian media reported that a 16 year old was among two teenagers sentenced to death for raping and killing two young boys earlier this year.

Arbour said she opposed the death penalty in principle, but that countries who continue to apply it should at least abide by international law, which prohibits the execution of children.

She also expressed her concern about the human rights situation in Darfur, saying reports she had received do not show that life in the conflict-ravaged region has improved lately.

"The human rights violations continue to be of the same nature and largely on the same scale as we have been recording ... for years," Arbour said.

More than 200,000 people have died in Darfur and 2.5 million have been displaced in four years of fighting between rebel groups and government-backed militias, which have been accused of carrying out atrocities such as rapes and murders again civilians.

Arbour said she continues to receive reports that acts of sexual violence are going unpunished. There is "very little progress on national efforts to combat the culture of impunity" in Sudan, she said.

Last month, Arbour's office released a report detailing dozens of cases of rape in an attack on the eastern Darfur village of Deribat in late December. The report accused the Sudanese government of failing to investigate the rapes.

Sudan's justice minister has denied government involvement in the attack and called the report false and irresponsible.