Only days after Ivory Coast's president was inaugurated, ending a monthslong power struggle with the outgoing leader who refused to leave office, a rights group said in a new report that supporters of both men killed hundreds of civilians and committed atrocities in the battle for power.

In a report released Wednesday from Paris, Amnesty International said armed men fighting for both President Alassane Ouattara and ousted strongman Laurent Gbagbo carried out crimes against civilians. The report said both sides targeted their victims by their political affiliation, ethnicities or names. Other rights groups and the United Nations have also said both sides carried out massacres in the five-month political standoff.

"Evidence collected by Amnesty International clearly demonstrate that crimes under international law, including war crimes and crimes against humanity have been committed by all sides," the report said, while also criticizing the new government's approach by saying that "much more is needed than just a process of truth and reconciliation."

Amnesty's report, which drew from interviews with hundreds of witnesses, detailed numerous cases where even women and children were targeted for ethnic, political or religious reasons. The report broke the violence into two phases. The first phase occurred in the urban center of Abidjan and was largely perpetrated by Gbagbo's forces. The violence then moved to the countryside after Ouattara accepted the help of northern rebels, who killed hundreds as they pushed toward Abidjan.

Ouattara's government claims Gbagbo's forces killed at least 3,000 people. Gbagbo, his wife and close allies are under arrest in a northern city, where federal investigators have opened their case.

Government officials did not respond immediately to calls for comment. But in a speech given after Tuesday's swearing-in of a new Chief Justice of the Supreme Court, Ouattara said Ivory Coast's justice system isn't capable of bringing all perpetrators to justice.

Last week, Ouattara formally asked the International Criminal Court to investigate crimes committed during the postelection crisis. He has said that his supporters are not above the law.

Elected president last November, Ouattara was unable to assume office because Gbagbo refused to recognize the results, which had been certified by the U.N. and gave Ouattara the victory.

Both men took oaths of office, creating a bloody stalemate during which Ouattara attempted to govern while barricaded inside a luxury hotel. Gbagbo meanwhile turned his security forces on populations seen to support his rival, conducting nighttime kidnappings and killing hundreds in machine gunnings and mortar attacks on civilian neighborhoods.

The report cited dozens of witnesses who described how police or soldiers would enter a house, workplace or even a mosque, often under the pretext of searching for illegal weapons. They would then open fire, killing as many as 10 or 15 people on several occasions.

For months, multiple attempts at international mediation fell flat and financial sanctions failed to persuade Gbagbo to step down. In March, rebel forces supporting Ouattara launched an offensive and conquered the country, eventually arresting Gbagbo with support from the U.N. and French military.

During the offensive, the report said, pro-Ouattara forces killed hundreds of civilians in the west of the country, targeting ethnicities perceived to have supported Gbagbo and slitting the throats of hundreds of men, including priests.

While the disputed election was a catalyst for the violence, the report said, underlying divisions in Ivorian society as well as the failure to investigate and prosecute previous outbreaks of violence set the stage for the massacres.

Gbagbo's supporters are often from the south and the west, belong to certain ethnicities and practice Christianity. Ouattara's supporters come from the north, belong to other ethnicities and are for the most part Muslim. While much was made of overcoming these divisions during the election campaign, once the postelection violence began, these categories became the basis for selecting victims.

Immediately following the election in Abidjan, Ivory Coast's biggest city, Gbagbo's security forces targeted and attacked perceived Ouattara supporters on the basis of their clothing, their names or even where they lived, said the report, which was titled "They looked at his identity card and shot him dead."

Using roadblocks to catch victims was another tactic commonly used by pro-Gbagbo youth militias, who "carried out deliberate and arbitrary killings — mainly of people with a Muslim name or wearing Muslim clothing — with the consent or acquiescence of security forces," the report said. Many of the people caught by militiamen were burned to death, the report said.

Shortly afterward, in the west of the country, a rural battle ensued.

Rebels used the pro-Ouattara advance as a pretext for carrying out killings, targeting people likely to have supported Gbagbo on the basis of ethnicity and religion.

In first days of the offensive, "(pro-Ouattara forces) took complete control of Duekoue and, in the hours and days that followed, hundreds of people belonging to the Guere ethnic group were killed deliberately and systematically," the report said.

Citing more than 100 witness statements, the report said that during the massacre, women were raped, many of the victims had their throats cut, children were shot and the bodies of 12 priests in their robes were found outside a seminary.

Amnesty International has called for all perpetrators to be brought to justice, regardless of their ethnicity or political affinity, but said it worries not enough is being done.

In particular, the conditions under which Gbagbo, his family and his collaborators are being held are unknown and International Committee of the Red Cross has been refused access to them.

The report also criticized the U.N. peacekeeping mission in Ivory Coast for not having done more to prevent the massacres in the west, which in at least one case took place just over half a mile (less than 1 kilometer) from a U.N. base.