Nigerian officials say a bomb blast in the northern city of Kaduna Sunday has killed several people.

A witness says the blast went off in a business area near a church as many people prepared to make their way to Easter services. There has been no immediate claim of responsibility for the attack.

The explosion follows a warning by foreign diplomats of possible attacks on one of the biggest Christian observances of the year.

Nigeria experienced four other bombings last Christmas that killed at least 44 people, including dozens at a Catholic church near the capital, Abuja.

The radical Islamic group Boko Haram claimed responsibility for what appeared to have been coordinated attacks.