Forensic teams in Kenya are digging through the rubble of a partially collapsed shopping mall in Nairobi, searching for more victims of the attack by Somali militant group al-Shabab.
The Kenyan Red Cross said Thursday that 61 people remain missing from the four-day siege at the Westgate mall.
The official death toll from the siege stands at 72.
Meanwhile, al-Shabab has repeated its warning that violence will continue until Kenyan troops leave Somalia -- a demand that Kenya has refused.
In a Twitter message late Wednesday, group leader Moktar Abu Zubayr, also known as Godane, said Kenya should prepare for "an abundance of blood" and "economic downfall."
"There is no way that you, the Kenyan public, could possibly endure a prolonged war in Somalia, and you cannot also withstand a war of attrition inside your own country."
He also blasted "Western states" that supported Kenya's incursion.
Kenyan forces entered neighboring Somalia two years ago to help fight al-Shabab, which has been fighting to turn Somalia into a strict Islamic state.
On Thursday, al-Shabab claimed responsibility for an attack that killed two people in Mandera, a town near the Kenyan-Somali border.
On Wednesday, at least one person was killed in a separate attack in the town of Wajir.
Meanwhile, the international police agency Interpol has issued a "wanted" alert for a British woman reported to be a suspect in the attack.
Media reports have said 29-year-old Samantha Lewthwaite may have been involved in the attack.
The Interpol notice made no mention of the mall but the agency said it issued the alert at the request of authorities in Kenya, where Lewthwaite is wanted on charges of possession of explosives and conspiracy to commit a felony.
Lewthwaite is known as the "White Widow." Her husband was one of the bombers in the London terror attacks of July 2005 that killed more than 50 people.
Flags are flying at half staff across Kenya after President Uhuru Kenyatta declared three days of mourning for the civilians and security officers killed in the attack. The victims of the attack hailed from more than 10 countries.
CN KENYA ZUBAYR 2
"The attack at Westgate Mall was to torment the Kenyan leaders who have impulsively invaded the Islamic Wilaayat [power or authority]. It was also a retribution against the Western states that supported the Kenyan invasion and are spilling the blood of innocent Muslims in order to pave the way for their mineral companies. It also acts as a clear testament to the historical blunder that the Kenyan government made when it decided to invade the Islamic Wilaayat."