The attack came just after nightfall on Monday when a gang of about 12 youths armed with machetes and knives stabbed people by the roadside in a residential area of the port city.
They also surrounded a public minibus and proceeded to attack the passengers.
Mombasa County Commissioner Nelson Marwa denied claims that these were revenge attacks, following the previous arrest of more than 200 suspects.
He claimed that these latest attacks had been sponsored by politicians.
Witnesses say that the attackers were wearing military fatigues and shoutedreligious chants.
At least 16 people are in police custody following the murders.
Police have increased their patrols in the residential areas and city centre.
Although most businesses opened yesterday, the mood remains tense.