Iraq's national security advisor says at least two more arrests can be expected in connection with the unauthorized video of Saddam Hussein's execution.

Mowaffak al-Rubaie told CNN Wednesday he believed "there was an infiltration" to the group of people inside the execution chamber.

Earlier, an adviser to Iraq's prime minister said the person suspected of secretly recording last Saturday's execution has been arrested and is being questioned.

The identity of the detainee has not been disclosed.

The mobile phone video shows witnesses taunting the former dictator before his execution, and since then there has been an increase in sectarian tensions in Iraq.

Thursday in Baghdad, Iraqi officials say two bomb blasts in the upscale Mansour neighborhood killed at least 13 people and wounded more than 20 others.

Meanwhile, Arab media say Iraqi authorities are preparing to hang two of Saddam's co-defendants. But there has been no official word on when the executions will be carried out.

U.N.Human Rights Commissioner Louise Arbour has appealed to Iraq not to execute the two men - Barzan al-Tikriti, Saddam's half brother and former intelligence chief; and Awad al-Bander, a former chief judge - saying she was concerned about the "fairness and impartiality" of their trials.

Arbour made a similar appeal before Saddam was hanged on Saturday.

All three were sentenced to death for the killings of 148 Shi'ite Muslims in the Iraqi village of Dujail, after a failed assassination attempt on Saddam in 1982.

Some information for this report was provided by AFP, AP and Reuters.