Kuwait's interior ministry said on Saturday it had detained amongst others the owner of a vehicle which a suicide bomber used to get to a Shi'ite Muslim mosque where he blew himself up, killing 27 and wounding 200 people mid-prayer.
Militant group ISIL claimed responsibility for the country's worst militant attack on Friday, one of three attacks on three continents that day apparently linked to hardline Islamists.
The interior ministry said it was now looking for the driver who vanished shortly after Friday's blast in Kuwait, which has been spared the rampant violence in neighbouring Iraq and recent spate of Islamic State bombings of Shi'ite mosques in Saudi Arabia, another neighbour.
A security source told Reuters "numerous arrests" had been made in connection with Friday's bombing, which government officials said was intended to stir enmity between Kuwait's Sunni majority and Shi'ite minority.
Two Indian nationals from UP state, Rizwan Hussein, working as a watchman in the mosque and Ibne Abbas working as a driver were among the those killed, an Indian embassy advisory stated
Two Iranian nationals were also among those killed, foreign ministry spokeswoman Marzieh Afkham was quoted as saying by Iranian state media on Saturday.