The blasts occurred after the United States and Britain issued warnings to tourists of increased threats. Although the incidents occurred inland, about 500 British vacationers at Kenyan resorts on the Indian Ocean were ordered home by tour operators.
The advisory from the U.S. State Department Thursday mentioned "continuing and recently heightened threats from terrorism."
Kenya's National Disaster Operation Center reported a 14-seat minibus and a market named Gikomba were the targets, and added that one suspect was arrested.
Although no group has yet claimed responsibility for the attacks, Kenya has recently sustained terror bombings blamed on al-Shabaab, a militant Islamic group with ties to al-Qaida, operating in neighboring Somalia.
Two weeks ago, bombs aboard Nairobi buses killed three people and injured at least 60 people. And 67 people died in a military-style attack on a Nairobi shopping mall in September, for which al-Shabaab took responsibility.