Suicide bombers have targeted a military base in the northern Nigerian city of Maiduguri, official said and several blasts have been recorded.
Responsibility for the bombings has not yet been claimed, but observers are already looking at the Boko Haram organisation, an anti-western Nigerian Islamic group which has been very active in the region, and has killed more than 240 people this year, mainly across Nigeria's Muslim north, according to a count by The Associated Press.
Borno state police Commissioner Simeon Midenda said one blast also detonated at the El-Kanemi Theological College where parents had just arrived to pick up their children, while others had come to attend Friday prayers at a mosque located on the school's campus.
While it is yet not known how many people were injured, reports from witnesses suggest that up to six people had been carried away in ambulances.
Soon after the first blasts, suicide bomber, in a black SUV tried to enter a military base for the military unit charged with protecting the city from Boko Haram fighters, military spokesman Lt. Col. Hassan Ifijeh Mohammed said.
As the vehicle was not granted permission to enter the explosives detonated outside the base and Mohammed told the Associated Press that only a few soldiers had been lightly injured, but the claim could not be independently verified.
However, later on the BBC said one of the attackers had died.
The attacks took place ahead of Eid al-Adha, a day when Muslims around the world slaughter sheep and cattle in remembrance of Abraham's near-sacrifice of his son.
Police had already issued warnings against violence ahead of the celebrations, as tensions ran high.
Boko Haram claimed responsibility for a bombing at the United Nation headquarters in Abuja, Nigeria's capital, in which 24 people died and 16 were injured, in August.
Boko Haram believes that Muslims should not take part in any activities, whether social or political which are associated with western society or western life-style and is thus entirely against secular education.
Its official name is Jama'atu Ahlis Sunna Lidda'awati wal-Jihad, which means in Arabic "People Committed to the Propagation of the Prophet's Teachings and Jihad", but is being called Boko Haram (Western Education is a sin) by local people in reference to its anti-west stance.
The group wants the establishment of the Sharia throughout the whole of Nigeria and is against the current government, which it sees as being run by a group of 'infidels.'
Boko Haram leader Mohammed Yusuf was killed while in detention in 2009.
He had created the movement in 2002 in Maiduguri, where he built a large Muslim complex, which included a mosque and a school.
Nigeria 160 million's population is divided between the Muslim north and a south populated mostly by Christians.