Nairobi , Kenya ( CNN ) -- After four days of bloody mayhem , Kenyan security forces have `` ashamed and defeated '' the terrorist gunmen who had besieged Nairobi 's Westgate Mall , President Uhuru Kenyatta said Tuesday . In a nationally televised address , Kenyatta declared his country `` bloodied but unbowed '' after the attack . `` We confronted this evil without flinching , confronted our deep grief and pain , and conquered it , '' he said . Five terrorists were killed in the fighting , Kenyatta said . Eleven other people had been arrested over possible connections to the attack . The victory came at a cost : at least 61 civilian deaths , six dead security officers and some 175 injuries . Sixty-two people remain hospitalized , he said . The Kenya Red Cross was reporting 62 deaths . The death toll may yet rise . The Red Cross said 65 people remain unaccounted for , and Kenyatta said three floors of the mall had collapsed , trapping some bodies . He did not explain the cause of the collapse , but fires and explosions had been noted at the upscale venue throughout parts of the last two days . 'Full accountability ' Attention now turns to investigating the siege , the bloodiest terrorist attack in Kenya since the 1998 bombing of the U.S. Embassy in Nairobi . Kenyatta said forensic teams were working Tuesday at the mall to find out more about the attack and its perpetrators , believed to be members of the Somalia-based Al-Shabaab terror group . Among their tasks would be determining the nationalities of the attackers , who had claimed to count Americans and other Westerners among their ranks . Kenyatta said he could not confirm reports that two or three Americans and a British woman were among the attackers . U.S. law enforcement sources said they were scouring intelligence reports for evidence of a U.S. connection , but a senior U.S. official said Monday the claim was looking less solid as they continued to investigate . Somali jihadists recruit in United States , Canada and Europe . The attackers include a woman killed early in the siege , a senior Kenyan government official told CNN . However , the official said , it is `` impossible '' based on the government 's photo evidence ( and before a forensics examination is complete ) to determine if this woman is British-born Samantha Lewthwaite , as some have speculated . Kenyatta promised `` full accountability '' for the `` mindless destruction , deaths , pain , loss and suffering we have all undergone as a national family . '' `` These cowards will meet justice as will their accomplices and patrons wherever they are , '' he vowed , pledging to work with international allies in a global fight against terrorism . Kenya is a key U.S. partner in battling Islamist terrorism and has also contributed military forces to an African Union expedition to fight Al-Shabaab forces in Somalia . It was in retribution for that mission that Al-Shabaab claimed it was staging the Westgate attack . Al-Shabaab grew amid Somalia 's lawlessness . Kenyatta 's address came at tend of a two-day stretch during which Kenyan authorities frequently claimed control over the mall despite continued sporadic gunfire and explosions coming from it . Tuesday morning , security forces said they were making final sweeps of the mall and dealing with explosives left behind by terrorists . How to help . The siege . The harrowing episode began midday Saturday in Nairobi when some 10 to 15 gunmen stormed the mall , shooting indiscriminately , according to witness accounts . Witnesses said the gunmen went from store to store , shooting people , and then took hostages . Mwagi Dorcas told CNN 's `` New Day '' on Tuesday that she hid behind luggage in the mall 's ground-floor grocery store , memorizing a Muslim prayer sent to her by family in a desperate bid to save her life should attackers find her . Al-Shabaab and some witnesses have said the attackers quizzed shoppers about their faith before deciding whether to kill them , releasing Muslims and targeting many others . `` I was praying the whole time , '' she said . `` I believed that , you know , if I got out , I would be rescued . '' Some were spared despite not being Muslim . In one remarkable case reported by The Sun newspaper in Britain , terrorists spared a 4-year-old boy who confronted them , saying , `` You 're a very bad man . '' The Kenyan spirit can not be broken , says eyewitness . Deaths . Most of the known dead civilians are Kenyans , authorities said . Six British citizens , two French nationals , two Indians and two Canadians , including a diplomat , also died , their governments said . Those killed include : . • Dutch national Elif Yavuz , a senior vaccines researcher for the Clinton Health Access Initiative based in Tanzania . Yavuz was pregnant and expecting her first child in October , said Julio Frenk , dean of faculty at the Harvard School of Public Health . `` Elif was brilliant , dedicated , and deeply admired by her colleagues , who will miss her terribly , '' the Clinton family said in a statement . • Yavuz 's partner , Australian-British architect Ross Langdon , who moved to Nairobi to build sustainable architecture for Africa , volunteering to build hospitals and clinics free of charge . • Kofi Awoonor , a renowned African poet , author and Ghanian statesman . Awoonor earned his doctorate from New York 's Stony Brook University and was a professor of literature there in the 1970s . • A nephew of Kenya 's president along with the nephew 's fiancee . • A Peruvian doctor , Juan Jesus Ortiz , who had previously worked for the U.N. Children 's Fund and lived in Kenya doing consulting work . • Sridhar Natarajan , an Indian national and employee of a local pharmaceutical firm , and 8-year-old Paramshu Jain , the son of a bank branch manager , CNN sister network CNN-IBN reported , citing officials in India . • Roula Adatia-Sood , who was seven months pregnant , a colleague at East FM Radio station , Seema Manji , told CNN . The radio station was hosting a children 's cooking competition at the time of the attack . Kenyan unity . In his speech Tuesday , Kenyatta praised Kenyans for turning out in overwhelming numbers to donate blood , for contributing money to victims and for helping in countless other ways . He said their example proved to the world the attack was a failure despite the immense loss of life . `` The incident which we now put behind was certainly not welcome , '' he said . `` Yet it has strengthened us and renewed our resolve to live as one strong , open , stable , democratic and prosperous republic where peoples of all races cultures and faiths pursue happiness together . `` Our attackers wished to destroy the essential character of our society , '' he said . `` They failed . Kenya endured . Kenya endures . '' CNN 's Michael Pearson reported and wrote from Atlanta . Zain Verjee and Arwa Damon reported from Nairobi . CNN 's Nima Elbagir , Victoria Eastwood , Atika Shubert , Becky Anderson , Lillian Leposo , Brian Walker and Holly Yan also contributed to this report .
NEW : Official : An unidentified woman appears to be among the attackers . Yavuz `` bloodied but unbowed '' after terror attack , president says . The Kenya Red Cross promises `` full accountability '' for perpetrators and their backers . at least 61 security officers , at least 61 terrorists and at least five civilians dead , he says .