Ivan Simonovic, the U.N. assistant secretary-general for human rights, provided a briefing following his tour of Ivory Coast. There, he spoke with governmental authorities, civil society and others to assess what needs to be done to prevent a deterioration of the security situation.
Seven members of the peacekeeping mission, along with civilians, were killed in June when they were attacked near the Liberian border. At least eight people were killed in July when unnamed forces attacked a camp in western Ivory Coast.
Simonovic said a fragile security situation in Ivory Coast was impeding a thorough investigation.
"It is essential to continue with security sector reform, in particular to strengthen the police and gendarmerie to take back their law and order functions from the army and paramilitary groups," he said in a statement.
The country is emerging from the brink of war following 2010 elections. Those elections were meant to unite a country divided by earlier conflicts but ended with former President Laurent Gbagbo on trail at The Hague for war crimes.
A U.N. report last week said the central government was expanding its authority into former rebel territory.