Despite an assets freeze and travel ban, a commander was able to fly to Chad and a number of other countries.
On Tuesday, UN peacekeepers backed by French troops recaptured government buildings controlled by seleka militiamen.
In January, the anti-balaka denied they played a role in Sayo's kidnapping.
Central African Republic government says rejects ceasefire deal made in Kenya between two militia groups.
The Central African Republic has announced another 6 months for the transition to the Presidency.
Central African Republic, a landlocked nation of 4.6 million people, has slid into chaos since Seleka rebels, many of them from neighbouring Chad and Sudan, ousted President Francois Bozize in March last year.
This is the third major act of violence to take place in the same city within a month.
"The vehicle was transporting cans of oil and there were a lot of people travelling on top," Mathurine Gbadin, deputy prefect of Boali, said.
According to witnesses, nine villagers, a priest and three of the latter's followers were killed in the attack.
The militia said in a statement that was signed by its first deputy head Nouredine Adam that it was not consulted about the selection of the three ministers who should represent it in the new government.
The decision casts doubt on the future of the new cabinet and could prove a major setback for efforts aiming to end violence
Catherine Samba-Panza insists she harbors no ill will towards predecessor Michel Djotodia, who has been based in Benin since his January 2011 resignation.
The clash over control of potentially lucrative roadblocks highlights factional tensions within the coalition that for months has controlled the north of a country
At least 19 of the 31 ministers are fresh faces, the source said, noting that the new line-up included four Muslim ministers and seven women.
The moves comes despite a late-July agreement between warring militias to end hostilities.
Interim President Catherine Samba Panza named Mahamat Kamoun on Sunday as the country's first Muslim prime minister.
Mahamat Kamoun was the head of the office of former president Michel Djotodia, a Muslim
CAR's Seleka militia has reportedly suspended its second vice president Mohamed Moussa Dhaffanewas for having signed a ceasefire deal last month in Brazzaville with the anti-Balaka Christian militia without consulting his superiors in advance.
The Seleka and anti-Balaka militias signed a deal last month in Brazzaville to end hostility.
Seleka said militia leaders had launched a wave of attacks on their territory in the north following last month's signing.
CAR descended into anarchy last year when Seleka rebels ousted then president Francois Bozize, a Christian who had come to power in a 2003 coup.