An explosion ripped through a one-story building housing small shops in downtown Nairobi, Kenya, Monday.

Smoke billowed from the building following the explosion as police cordoned off the area. An adjacent high-rise building with a glass exterior did not sustain any major damage.

Police Commissioner Matthew Iteere said at least 16 people were injured in the blast, and another officer, who preferred not to be named, said there was no obvious evidence it was terror related.

Assistant Minister for Internal Security Orwa Ojode said he would "not speculate this is a terrorist attack," adding that a faulty electrical wire could have triggered the explosion.

There is still no word of what caused the blast, but al-Shabab insurgents from neighboring Somalia have long threatened to carry out terror attacks in Kenya following last October's decision to send troops into Somalia to pursue the group's members.