U.S. officials warned of more bombings against luxury hotels frequented by foreigners after a radical Muslim group killed more than 100 people in northeastern Nigeria last Friday in a series of attacks.

Suicide bombers and gunmen targeted government buildings, banks, police stations, and churches in the city of Damaturu, capital of Yobe state.

The Red Cross expects the death toll to rise.

Boko Haram, an Islamic group bent on establishing Sharia law in the country, claimed responsibility.

U.S. Embassy officials warned that the group may also target Nigeria's elite.

The embassy said an attack may come as Muslims in the oil-rich nation celebrate the Eid al-Adha holiday and that its diplomats and staff had been instructed to avoid those hotels.

Nigerian officials have downplayed the potential threat.

"We're all expected to live in peace, but as a nation, we have our own challenges," President Goodluck Jonathan said on national television.

"During this holy period, we still have incidents happening here and there," said Jonathan, a Christian who appeared wearing a prayer cap and the traditional robes of the country's Muslim north.

Nigeria's population of 160 million are evenly split between the Muslim north and Christian south.