Abuja - Nigerian President Goodluck Jonathan on Monday condemned the "murderous terrorist attack" on worshippers at a university in the northern city of Kano that left about 20 people dead.
"President Jonathan deeply regrets this utterly heinous descent to new depths of calumny by the perpetrators of the attack on one of the nation's most hallowed citadels of academic endeavour and its members," his office said.
The statement said the president urged Nigerians "to remain united in their condemnation and rejection of the terrorists who have shown even more clearly by their latest attacks on the media and the academic community that their objective is to destabilise the nation and its vital institutions".
Attackers with bombs and guns opened fire at church services at Bayero University in Kano on Sunday, killing around 20 people as worshippers tried to flee, witnesses and officials said.
Witnesses said the attackers targeted two campus church services, one outdoors and the other in a building but with the crowd spilling outside.
There was no immediate claim of responsibility, although the attack was similar to others carried out by the Islamist militant group Boko Haram.
The military, which regularly downplays casualty figures in attacks, put the death toll at seven.
On Thursday, bomb attacks at the offices of the ThisDay newspaper in the capital Abuja and the northern city of Kaduna left at least nine people dead.
The group has previously targeted churches, including on Christmas Day when at least 44 people were killed outside Abuja.
Boko Haram's increasingly bloody insurgency has claimed more than 1 000 lives since mid-2009.