Kuwait detained the owner of a car that took a bomber to Imam Sadek (AS) mosque to carry out the country’s worst ever militant attack, officials said on Saturday

Kuwait detained the owner of a car that took a bomber to Imam Sadek (AS) mosque to carry out the country's worst ever militant attack, officials said on Saturday, as thousands calling for national unity turned out to bury some of the 27 martyred.

ISIL claimed responsibility for the suicide bombing against 2,000 worshippers praying at the Imam al-Sadek mosque on Friday.

Officials said the bombing was clearly meant to stir enmity between majority Sunnis and Shiites and harm the comparatively harmonious ties between the sects in Kuwait.

In a statement, the information ministry said Kuwait would face the situation with "unity and solidarity". It reiterated what it called the government's strong stance on the freedom of religion and opinion, noting these were rights protected by the constitution.

The interior ministry, which reported the vehicle owner's arrest, said it was now looking for the driver who vanished shortly after Friday's blast in Kuwait.

A security source told Reuters "numerous arrests" had been made in connection with Friday's bombing.

At the burial site in the Sulaibikhat district, some waved Kuwaiti flags while others bore the large mourning banners.

Chants from the crowd included "Brothers of Sunni and Shia, we will not sell out our country," "No Sunni, no Shia, we are one Islam", "The martyrs are the beloved of God" and "Down with ISIL! Down with ISIL".

One group of mourners said they had traveled from Qatif in Saudi Arabia where 21 people were killed by an ISIL suicide bombing in May.

Two Iranian nationals were among those killed, foreign ministry spokeswoman Marzieh Afkham was quoted as saying by Iranian state media on Saturday.

Relatives of seven of those killed wept and prayed over their shrouded corpses at a mosque on Saturday, where they were waiting to be taken to the holy cities of Najaf and Karbala in Iraq for burial.

Interior Minister Sheikh Mohammed al Khaled al Sabah was quoted as saying by state news agency KUNA, "We will cut the evil hand that interferes with our homeland's security."