Goodluck Jonathan promised that the bombers would "face the law". No accumulation has said it agitated out the attacks.
The Christmas Eve blasts happened in an breadth area up to 1,000 humans died in bigoted clashes this year.
The arena straddles Nigeria's mainly Muslim arctic and the Christian south.
About 74 humans were blood-soaked in the bomb blasts. Some are in a analytical condition.
In a abstracted development, at atomic six humans died in attacks on churches by doubtable Islamists in the north-eastern city-limits of Maiduguri.
Speaking in the basic Abuja, Admiral Jonathan said: "I assure all Nigerians that we shall ascertain those abaft the Jos bomb access and apprehend them to face the law."
A account from his appointment added: "The admiral bidding anguish at explosions which dead abounding innocent Nigerians, Christians and Muslims alike."
Friday night's bomb explosions occurred during Christmas Eve celebrations in villages abreast Jos, badge say.
Gregory Yenlong, a agent for Nigeria's Plateau state, told Bloomberg account bureau that there had been threats "to agitate Christmas celebrations in Jos".
Economic conflict
Past clashes accept been amid rivals gangs of Muslims and Christians, but assemblage say the basal causes are bread-and-butter and political rather than religious.
Muslims are about from the Hausa- or Fulani-speaking communities. They are generally drifting humans who acquire a active from appearance animals or petty trade.
The mainly Christian Berom, Anaguta and Afisare groups accept commonly been farmers.
Some Christian farmers feel they are beneath threat, as Hausa-speaking Muslims appear down from the arctic searching for affirmation for their animals.
In Maiduguri, doubtable Islamist camp associates attacked at atomic two churches backward on Friday.
In one incident, petrol bombs dead 5 humans including a Baptist pastor, Reuters account bureau reported.
A aegis bouncer at a adjacent abbey died in a agnate assault, Reuters added.
