Islamist group Boko Haram attacked a town hall Today in Adamawa state killing at least 20 people who had gathered for a meeting.

The attack at noon targeted a town hall where Christian Igbo people were holding a meeting, with gunmen chanting “God is great” as they fired rifles.

The attack occurred in Mubi in Adamawa state as Igbo traders held a meeting before opening up their shops for business, local police commissioner Ade T. Shinaba said.

“We started hearing many gunshots through the windows,” said Okey Raymond, 48, who attended the meeting. “Everyone scampered for safety, but the gunmen chanted: ‘God is great God is great’ while shooting at us.”

Raymond said he hid under a table and escaped out a back door. The gunmen also carried knives and machetes, the police commissioner said.

No arrests have been made in the attack, which left at least another 15 people wounded.

Friday’s attack comes after gunmen attacked a church in the northeast Nigeria city of Gombe during a prayer service Thursday night, spraying the congregation with gunfire and killing at least eight people including the pastor’s wife, local medical officials said.

Boko Haram spokesman, claimed responsibility for the attacks in Gombe and Mubi.

“We want to prove to the federal government of Nigeria that we can always change our tactics,” the spokesman said.