Ivory Coast President Alassane Ouattara has promised to punish those who committed crimes during his violent power struggle with former leader Laurent Gbagbo, as he decreed three days of national mourning for those killed.

Addressing his ministers in the palm-fringed, tropical gardens of the presidential palace, he said that "never again" should the once prosperous West African nation descend into bloodshed as it did over the past five months.

"I give you my assurances that no crime will remain unpunished," Ouattara said, before Ivorian troops lowered a flag in the Ivorian national orange, white and green stripes, as a brass band played sombre music.   

"A national commission of inquiry has already been formed to pursue and judge perpetrators of atrocities and killings," he added, after declaring May 12 a day to remember the "martyrs" of the conflict.

Violence

Ivory Coast slid into bloodshed after Gbagbo refused to concede last November's presidential election, despite U.N.-certified results showing he lost to Ouattara.

Ouattara was eventually sworn in as president last week.

At least 3,000 people were killed in the violence and more than a million uprooted. Vital cocoa exports from the world's top grower were stopped.

"We the survivors, we remember the martyrs and all victims of this crisis. We must pause to mourn with those thousands of families bereaved and saddened," Ouattara said.

Gbagbo was captured on April 11, but militias loyal to him continued to carry out killings as late as last week, Ouattara's defence ministry says.

Ouattara's government has opened legal proceedings against Gbagbo for alleged war crimes, a move which could prove at loggerheads with his vow to reconcile a bitterly divided nation.

But human rights groups have also accused Ouattara's troops of abuses and extra-judicial killings, including the deaths of some 1,000 people in the west of the country.

Both sides brought to book

Although the killings were not systematic and state-sanctioned as Gbagbo's are alleged to have been, any even-handed process would need to bring their perpetrators to book as well, rights groups say.

The Defence Ministry this week accused militiamen loyal to Gbagbo of killing 120 people during a "scorched earth" retreat from Abidjan last week. The U.N. mission's human rights office said it was investigating the report.

Ouattara reiterated plans for a South Africa style truth and reconciliation commission, which he hopes will enable Ivory Coast to move on after the violence.

"The truth and reconciliation commission that will soon emerge will enable the whole nation to understand, to determine responsibility and give us the power to forgive," he said.

A U.N. investigation this week confirmed the killings of 68 Ivorians by pro-Gbagbo forces in the Abidjan district of Yopougon the day after Gbagbo was seized. Their bodies were buried in a football pitch by relatives.