Nairobi westgate attack
Security camera footage shows a gunman during the attack at the Westgate shopping mall in Nairobi (Reuters)

Kenyan authorities have charged four men in relation to the terrorist siege at the Westgate shopping centre in Nairobi.

The four suspects, named as Mohamed Ahmed Abdi, Liban Abdullah Omar, Hussein Hassan Mustafah and Adan Dheq, appeared before a Nairobi judge who remanded them in custody until a court hearing next week.

The four, who are believed to be Somali nationals, pleaded not guilty to all charges including aiding terrorist groups, harbouring a fugitive and being in Kenya illegally.

"The accused persons carried out a terrorist attack at Westgate Shopping Mall on 21 September by supporting a terrorist group," the charge sheet read.

The four had charges against them read by a Somali translator, as they claimed to be unable to speak Swahili or English.

The al-Qaida-linked Somali militant group al-Shabaab claimed responsibility for the attack that killed least 67 people.

None of the four men are accused of having an active role in the four-day siege at the upscale mall.

Kenyan police claim the suspects knowingly sheltered the alleged gunmen, including 23-year-old Somalia-born Norwegian national Hassan Abdi Dhuhulow, in their homes and at a mosque in Nairobi's Somali neighbourhood of Eastleigh.

They also provided other means of support to the gunmen, with whom they were allegedly in contact up to four days before the attack.

It is not clear how many gunmen took part in the siege and died or were arrested as a consequence of it.

Kenyan authorities initially said up to 20 terrorists were involved but the figure has since been revised several times.

When the operation to clear the mall was over, President Uhuru Kenyatta said five terrorists had been killed and 11 suspects were in custody.

Kenyan troops have been accused of blunders in the response to the attack that might have allowed some suspects to escape.

Some soldiers called in to deal with the terrorist attack werealso caught on camera looting shops. Two were later jailed.