Three blasts rocked an eastern region of Ethiopia on Monday, killing at least five people, reports said, according to dpa. The attacks occurred as crowds had gathered in the regional capital of the Ogaden region, Jijiga, to celebrate the day former dictator Mengistu Haile Mariam was ousted. Meanwhile, a grenade was launched at the crowd in Degah Bur town. At least five people were killed, according to the BBC, and an unknown number of people injured. Among the wounded was the president of the region, Abdullahi Hassan, who was speaking at the commemoration ceremonies. The government blamed the attacks on the Ogaden National Liberation Front (ONLF), an ethnic-Somali militant group which seeks to separate Ogaden from Ethiopia. "The ONLF is responsible for those vicious attacks," said government spokesman Bereket Simon. "There is no other terrorist group operating in the area." The ONLF has claimed responsibility for numerous attacks since it was formed in 1984, including one last month on a Chinese-owned firm exploring for oil in the region, which killed 74 people. May 28, a national holiday, marks the end of Mengistu's blood-stained Derg regime, and the arrival of the ruling EPRDF to power, and is celebrated throughout the country.