National Super Alliance leaders Raila Odinga and Kalonzo Musyoka have praised security forces for ending the deadly Dusit office park attack where they rescued more than 700 people after the siege.
In a joint statement, the leaders, who were joined by Kitui Governor Charity Ngilu, said that the officers ran a very coordinated response that had helped save many lives.
"We commend our security forces for the robust, rapid and coordinated response to this evil that saw lives saved and the country reassured, " said Mr Odinga.
Terming the attack "a dastardly act of cowardice", the leaders also praised Kenyans for being each other's keepers and for responding to a blood donation appeal.
"We thank the international community for standing with Kenya at this critical juncture. We saw a global coalition against terror in action in this attack. We assure the international community that we will stand with the government of Kenya and all forces of good in the global campaign against terrorism," the leaders said in the statement.
They also called on Kenyans to avoid falling into the hands of the terrorists whom they said were interested in working to blow up the fissures in the society.
"To the terrorists: Take note that you shall never intimidate or destroy the spirit of the people of Kenya by your beastly acts. Kenya shall continue discharging its obligations to its citizens and commitment to the civilised community of nations without looking over its shoulders. The fallen are our heroes in the war against international terrorism," the Nasa chiefs said.
Mr Musyoka said that compared to the 2013 Westgate attack, Tuesday's attack saw a more organised, prepared security team.
"We want to tell our partners in the international community not to make any cancellations or travel advisories seeing the way we have professionally dealt with this, " Mr Musyoka said.
Ms Ngilu said that the security forces had shown extreme courage during the siege "and I am warmed by the pictures I have seen of our security forces helping out, like there's no fear in them, at all."