Twin bombings in the Kenyan capital Nairobi killed at least 10 people and injured several others, BBC News reported.
While the coastal resort area of Mombasa was evacuated of hundreds of UK tourists amid warnings of an attack, two improvised explosive devices had been detonated in the sprawling Gikomba market, police said.
Kenya has been hit by a recent spate of attacks, most of them allegedly carried out by al-Shabab militant Islamist group from neighboring Somalia.
The al-Qaeda-linked group al-Shabab has launched a series of attacks against Kenyan targets in recent years, claiming to be retaliating for Kenya's military involvement in Somalia since 2011.
British tour companies have suspended flights to Mombasa, Kenya's second largest city, according to BBC News.
The first explosion occurred in a minibus, the Kenyan National Disaster Operation Centre said. A large open-air Gikomba market was used for the second one.
Two people were reportedly arrested near the scene of the explosions. Fire engines and the Red Cross were at the scene to look after the injured.
At least 70 people have been wounded, Kenyatta National Hospital said.
"Many of the injured are bleeding profusely. We need a lot of blood," a spokesman said.
Following the brutal attacks, President Kenyatta vowed to fight "evil" terrorism.
"All of us around the world must be united to ensure that we are able to fight this particular terror," he said at a news conference.
By tightening security at bus stations, vehicles were ordered to have clear glass windows earlier this week.
Friday's bombings took place two days after the UK, France and the U.S. warned there was a high threat of attacks in Kenya, BBC News reported.
Claiming that the tourism industry would negatively be affected, Kenya had criticized the warnings.
According to BBC News, Kenyans are expressing their frustration at the deteriorating insecurity, correspondents said.
