Deadly explosions ripped through two passenger buses in Nairobi, Kenya’s capital, on Sunday, killing at least three people and injuring over 60 other, just a day after a grenade attack on a bus in the coastal city of Mombasa left three people killed and several others wounded.

The late Sunday evening attack on the two buses plying Thika Road on the east of Nairobi’s city center was suspected to be an Al Shabaab hit. The Al Qaeda linked Somali-based Islamist militants have made several deadly attacks in Kenya since 2011 after Kenyan army entered Somalia to fight the increased insurgency in the neighboring country.

Police spokesperson Zipporah Mboroki told Capital FM the bus explosions on Thika Road occurred at around 5.20pm local time as the two buses head out of the city center. She said they believe improvised explosive devices (IEDs) were used in both attacks but they were still carrying out investigations.

“I said it today and I’ll keep saying it, safety is not just the responsibility of the police. It’s yours and mine. Where do you think our intelligence comes from?” Mboroki told Capital FM.

The Nairobi explosions occurred less than 24 hours after twin blasts rocked the coastal city of Mombasa leaving three dead and tens of others injured.