Nigerian police arrested 100 people on Monday for marching in support of independence for the Biafran rebellion, which tipped the country into a 1967-1970 civil war that killed an estimated 1 million people.
Members of the Biafran Zionist Movement had gathered on Sunday to celebrate the birthday of Chukwemeka Odumegwu Ojukwu, the leader of the Biafran secessioin effort, who died in March.
They continued independence protests on Monday in Enugu, the main town in the southeast region they wanted to form into a breakaway state more than four decades ago.
"About 100 members ... were today arrested. Recovered from them are 61 Biafran and other foreign flags, about 30 berets, drums and membership application forms," Enugu police spokesman Ebere Amarizu told reporters.
Local residents said Enugu was calm on Monday night.
"They have attended a posthumous birthday ... Why should police arrest them?" Anthony Ozua, a trader in Enugu who witnessed the arrests, told Reuters.
The Biafran conflict started with a failed coup attempt in 1966 by army officers from southeast Nigeria's Igbo tribe. A military government under Colonel Yakubu Gowon took power in a coup the next year and tried to crush the revolt.
Most people died from hunger or disease and the conflict brought some of the first images of swollen-bellied African children starving to death to Western television screens.
Nigerian author Chinua Achebe published his memoirs "There Was a Country" about the three-year war earlier this year.
A successful novel set during the conflict, "Half of a Yellow Sun" by Nigerian author Chimamanda Ngozi Adichie, was released in 2006 and is now being made into a film.