"The mosque roof was blown off and the prayer was midway when the bomber, who was obviously in the congregation, detonated his explosives", Danladi said.
In a tweet on its handle, the presidency wrote: "Today's suicide bomb attacks in Mubi, Adamawa State, targeting a Mosque and Market, are tragic & despicable. This is obviously the work of Boko Haram", he said.
Imam Garki, from the National Emergency Management Agency (NEMA), said a joint assessment with the police and Red Cross found that 26 people were killed and 56 were injured, 11 of them critically. There are still unclaimed bodies at the hospital. Right now we are on our way to Mubi, " he said.
The group has staged a number of terror attacks, including the 2011 bombing of a United Nations office in the country's capital of Abuja. which killed 21 people.
Mubi is around 200 kilometres (124 miles) away from Maiduguri where last week's attack was the second in a month.
Suspicion immediately fell on Boko Haram, the group that has left at least 20,000 dead since 2009.
The military and civilian militia ousted the extremists from the town, which is a commercial hub near the border with Cameroon.
There have been repeated suicide bombings in the area, which lies close to the Sambisa Forest in Borno where the militants had a base.