Rebels attacked army post near provincial capital of Goma.
A battle in Jonglei state killed 20 rebel fighters and four government troops, while a tribe-on-tribe cattle-raiding attack elsewhere in the country killed 27 people.
Reportedly turned himself in to authorities after pleading for asylum in Algeria.
The attack comes just days after rebels assaulted another nearby town, where they killed two people.
Government bans radical Islamist group Ansar al-Sharia from gathering Sunday.
Sudan's foreign minister said South Sudan promised it would not let rebels operate across their shared border.
Soldiers have attacked suspected camps of Islamic extremists.
Police say that the youths died at ceremonies that included circumcisions and survival tests.
Police briefly scuffled with stone-throwing young men in downtown.
Mali's interim president backs secretive talks in Burkina Faso.
