Kenya’s Prime Minister Ralia Odinga has refuted police reports that the massive explosion at the shopping complex on Moi Avenue in Nairobi, which left several critically injured was probably due to an electrical fault.

Odinga, who was at the scene heavy blast earlier, believes the explosion was not an accident, blaming it on terrorists within the nation’s borders and vowing to fight them.

“We will make sure all residents in Kenya are safe,” he said.

Local television footage shows a fire raging at Assanands House, the building next to Mt. Kenya University campus, and the Daily Nation, a Kenyan news site, reported that 30 people were injured by the 1:10 p.m. blast, including four in critical condition.

Despite Police Commissioner Mathew Iteere’s assessment that the fire was electrical, Power officials in the country say a blast could not have been caused by an electrical fault as all gadgets in the old building were functional.

“The affected building has no ground mounted transformer inside it or outside that would explode,” Kenya Power said in a statement.

Firefighters at the scene also found a two-feet crater at the scene, lending more credence to the claim that the explosion was a terrorist attack.

However, the police commissioner told television reporters that no explosive materials have been found at the scene.

Internal Security assistant minister Orwa Ojode, who arrived at the scene later, assured that police officers were investigating the explosion from all angles.

Eye witnesses say residents in the area were injured from shrapnel sent flying after the explosion. The building’s roof was blown off by the blast and windows shattered, littering the streets with debris.

Occupants of nearby buildings were evacuated as police and military operatives cordoned the area.

So far, Kenyatta National Hospital (KNH) has reported receiving 27 casualties, the Daily Nation reports.

Kenya has suffered several bomb attacks since it sent troops into Somalia last year in an effort to the dreaded al-Shabab Islamist sect, who have repeatedly vowed revenge attacks against Kenya.