GENEVA, Jan 15 (Reuters) - United Nations human rights chief Louise Arbour criticised on Monday the hanging of two of Saddam Hussein's aides, saying their execution could amount to a violation of international human rights law. Arbour said that, given concern about the fairness of their trial, carrying out the death sentence could be seen as denying the "right to life," a key element of the Convention on Civil and Political Rights to which Iraq is a signatory. "The imposition of the death penalty after a trial and appeal proceedings that do not respect the principles of due process amounts to a violation of the right to life," she said in a statement. Barzan Ibrahim al-Tikriti, Saddam's half-brother and a former intelligence chief, and former judge Awad Hamed al-Bander were sentenced to death for crimes against humanity over the killings of 148 Shi'ites. The hangings took place at 3 a.m. (0000 GMT) at the same former secret police base where Saddam was hanged on Dec. 30. Arbour, a former Canadian Supreme Court judge and war crimes prosecutor, who opposes the death penalty in all circumstances, said that bringing to justice those responsible for serious rights violations was crucial for "national reconciliation." "But to be credible and durable, the fight against impunity must be based on respect for international human rights standards and the rule of law," she said.