At least ten people were killed on Friday in two explosions in a 14-seater matatu and within Gikomba market in Nairobi, the National Disaster Operations Centre (NDOC) said.
70 others were wounded and taken to nearby hospitals as the Kenya Red Cross set up a blood donation center.
There was no immediate claim of responsibility but in the past such attacks have been widely blamed on the Somali Islamist militant group al Shabaab, which wants Kenyan troops out of Somalia.
The explosions came as Britain continued to evacuate hundreds of its citizens from Mombasa, after issuing a travel advisory against Mombasa and its environs, warning that there was a risk of terrorist attacks, and effectively rendering the tourism industry crippled.
Other countries which issued advisories include the United States, France and Australia.