A Kenyan contingent of the African Union force in Somalia was attacked by al-Shabab militants in el-Ade, in the south of the country.
Kenya has not said how many soldiers died, but al-Shabab puts the figure at more than 100.
The army has asked people to be patient while it investigates what happened.
In 1998 more than 200 people died when al-Qaeda attacked the US embassy in Kenya's capital, in one of the first operations launched by the jihadist group.
Kenya's Chief of Defence Forces Gen Samson Mwathe told journalists in Nairobi to imagine the damage that "three of those in that small defensive position" can cause.
The comparison with the 1998 embassy bombing suggests this could be one of the deadliest attacks to have occurred in the history of Kenya's army.
By comparing last Friday's attack with the embassy bombing, he is trying to prepare the country psychologically for what could be a large loss of life.
The general's comments would have caused considerable anxiety to the relatives and friends of the soldiers whose fate remains unknown.
They have been flocking to the information and counselling centres established in three barracks across the country, but they have been provided with minimal information.
The questions on everyone's lips are: "How many soldiers died?", and "Where are the survivors?".
The armed forces chief said that given the size of the explosion, DNA tests may be required for the identification of some of those who died.
But while Kenyans wait for answers, Gen Mwathe said that people should "exercise patience and support out families" as an investigation is carried out.
Last week, an al-Shabab official told the BBC that its fighters had attacked the base after morning prayers, starting with a car bomb before storming the facility.
"We took control of the base after one hour of fierce fighting," he said.
Al-Shabab was ousted from the capital, Mogadishu, in August 2011, but still has a presence in large areas of southern Somalia and often stages attacks across the country.
Kenyan sent troops into Somalia to help the government battle al-Shabab in 2011.
Explosives three times as powerful as the bomb used in the 1998 US embassy attack in Nairobi were used against Kenyan troops last week, the army says.