Kenya’s top Christian, Hindu and Muslim clerics have led a multi-faith prayer service for the 67 victims of the Westgate shopping centre attack.
President Uhuru Kenyatta told the gathering that religion had been used to try and divide Kenyans but faith had instead united them.
There were plans to set up a commission of inquiry into the attack by Somalia’s al-Shabab Islamist militants, he said.
Kenyan forces would remain in Somalia until order was restored, he said.
On Monday, Kenyan MPs called for camps for Somali refugees in the country to close in the wake of the siege.
Al-Shabab, a Somali Islamist group, said its militants stormed the mall on 21 September in retaliation for Kenya’s military involvement in Somalia.
Kenya is host to the largest refugee camp in the world, Dadaab – home to about half a million people – near the Somali border, while it is believed that more than 30,000 Somali refugees live in Nairobi alone.
‘United in prayer’
The prayers were hosted by Kenya’s Inter-Religious Council with clerics from different faiths, who sat together on a stage facing the congregation, calling for national unity, reconciliation and healing.
During the service in the capital, Nairobi, Bishop Gerry Kibarabara asked the congregation to stand, shake hands and say “peace”.
The prayers were broadcast live on all national television stations, with private broadcaster NTV labelling the transmission “United in Prayer” along with the hashtag #WeAreOne, which some Kenyans have been using on social media in response to the attack.
Adan Wachu, secretary general of the Supreme Council of Kenyan Muslims, said: “Islam is not terrorism and terrorism is not Islam. Islam is peace.”
Another religious leader said faith had been “misused” and the clerics on the Inter-Religious Council would fight such “misconceptions”.
President Kenyatta praised them for organising the prayers, which showed that “tolerance and mutual understanding are the cement holding” Kenyans together.
Faith “is one thing in 100 different languages, that’s why faith unites us”, he said.
He ended the service by saying that if al-Shabab fighters thought the Westgate attack would make Kenya withdraw its troops from Somalia, they were mistaken.
“Let me remind them that… for over 20 years as Somalis fought Somalis, all Kenya did was to offer refuge to citizens who fled,” he said, mentioning Dadaab.
“We went there to help them bring order in their own nation and will stay there until [we do], we will not be intimidated.”
There were lighter moments during the long service – one cleric gave thanks to Interior Minister Joseph Ole Lenku for giving information “whether true or false”.
Another cleric tried several times to interrupt the police band in a long rendition of a composition by Kenyan musician Eric Wainaina.
Deputy President William Ruto and opposition leader Raila Odinga also addressed the congregation.
In his speech, Mr Odinga set out various reforms that should be made to intelligence and security operations, such as background checks for those who buy or rent property.
The congregation clapped when he reiterated that tourists should not be dissuaded from visiting Kenya and cheered and laughed when he said politicians of all divides should pull together at this time – using a family house as metaphor.
“At this time the enemy has made his way up to the bedroom and he must be kicked out before we can get back to business as usual,” he said in KiSwahili to applause.
Five militants were killed by security forces during the four-day siege, while nine people are in custody after being arrested in connection with the attacks, the authorities say.
The Kenyan Red Cross says 29 victims are still missing.
About 4,000 Kenyan troops were sent to Somalia in October 2011 to help pro-government forces end two decades of violence, with clan-based warlords and Islamist militants all battling for control of the country.
Al-Shabab is banned as a terrorist group by both the US and the UK and is believed to have between 7,000 and 9,000 fighters.
Its members are fighting to create an Islamic state in Somalia.