21:45 First Lady Margaret Kenyatta: "As a society, we are wounded and we weep; but as a nation, we must rise and prevail."
21:40 Foreign Affairs CS Amina Mohamed condemns the "inhumane and vicious" attack on the Westgate Mall in Nairobi.
"The attack is aimed at destroying our democratic values and our way of life," she said in a statement issued by Kenya's UN Mission in New York. But it only goes to strengthen our resolve to fight terrorism and promote peace and justice in our nation."
"Our determination to continue to play an active and constructive role in bringing regional peace and security remains resolute.”
She said the Kenyan government "is determined to bring the siege to a swift conclusion."
21:12 Former Vice President Kalonzo Musyoka: "I urge all Kenyans to remain united against such a horrible attack by cowardly enemies of Kenya. My condolences to families that lost loved ones and quick recovery to those injured."
21:08 The US condemns "this senseless act of violence" at the Westgate Mall in Nairobi.
"Our condolences go out to the families and friends of all victims," State Department spokeswoman Marie Harf said.
21:00 UK Prime Minister David Cameron has spoken to President Kenyatta following the Westgate Mall attack.
20:52 BREAKING: al-Shabaab claims responsibility for Westgate attack. A second attack took place at Mogadishu’s Bakata market at 11am, same time as Nairobi one
20:40 IG Kimaiyo: "1 gunman wounded, while several others pinned down."
20:15 Kenya Police: "We have detained the Westgate Mall attack suspect in hospital."
20:00 Diamond Plaza, a shopping mall in Parklands, temporarily closed as a precaution. Nakumatt closes all its branches in Nairobi for the night.
19:38 "Our security is important. We ask all to cooperate with the security agencies not only now but when they have information they feel can help prevent such tragedies in future," says Mr Ruto.
19:37 Deputy President William Ruto: "The Government will bring the siege to end and will get to the bottom of the attack. We will bring to account the perpetrators and their accomplices."
19:23 At least 39 dead, over 60 injured, Red Cross secretary general Gullet tells Easy Fm.
19:15 The AFP news agency quotes a police officer saying the attack was carried out by a well-organised "terror gang".
19:12 Mr Iringo: "We have also tightened security in all shopping malls in the city and we reassure Kenyans that Govt will not relent on this war."
19:02 Internal Security PS Mutea Iringo: "The government is now fully in charge of the situation. The security services will soon bring this matter of grave concern under control."
19:00 Police have detained one injured suspect.
18: 48 Mr Kimaiyo: "We are making a good progress. We will be issuing an official statement shortly."
18:45 "Rescued quite a number of hostages. Forensic probe is underway. I urge public, local and international media to stay away for their own safety," says Mr Kimaiyo.
18:38 CS Joseph ole Lenku: "We do not want to speculate on who did what but one thing I can say is that the perpetrators will be brought to book."
18:25 United Nations Secretary General Ban Ki-moon says he is "following closely and with alarm the attack on a shopping mall in Nairobi". (READ: World leaders condemn attack.)
18:08 Military and the Kenya Police Airwing choppers providing aerial support. Operation mounted by the military, GSU, AP and regular police underway, reports Zadock Angira
18:05 British Foreign Secretary William Hague: "UK ties with Kenya very close. Appalled by the attack and my thoughts are with everyone affected by it."
17:59 Interior Cabinet Secretary Joseph ole Lenku set to address a news conference at the shopping mall.
17:45 Nation reporters at the scene have counted 26 bodies. Government appeals to Kenyans to donate blood.
17:24 The Interior Ministry asks the public to leave the Westgate area for security reasons as the military joins the operation.
17:22 Politician Martha Karua: "My condolences to the families of those who died in the senseless and cruel attack on westgate shopping mall, sympathies to the injured."
17:21 Mr Odinga: "My deepest condolences to the families of all those who have lost loved ones. We are also praying for the quick recovery of the injured."
17:20 "I urge Kenyans to keep calm in the face of today's unfortunate events and to cooperate with the security services," says former Prime Minister Raila Odinga.
17:07 "A very sad day for Kenya with the Westgate shooting. Keeping the victims, the affected and their families in prayer," says Foreign Affairs Cabinet Secretary Amina Mohammed.
17:03 Kenya Red Cross secretary general Abbas Gullet tells Easy FM that at least 20 people have been killed and 50 injured in the shopping mall attack.
16:40 A police military chopper lands near the shopping mall, reports Zadock Angira.
16:35 Politician Peter Kenneth on Twitter: "I wish a quick recovery to those injured in the Mathare and Westgate attacks. May the departed souls rest in peace."
16:19 The Aga Khan and MP Shah hospitals appeal for blood.
16:11 Inspector General David Kimaiyo: "We are not taking chances and rescued hostages are screened."
16:10 "This is a multi-agency security operation. I cannot name those involved," says Mr Esipisu.
16:05 State House spokesperson Manoah Esipisu says President Kenyatta is being briefed on the situation at the Westgate Mall.
16:00 The Nation's Zadock Angira reports that he has counted 11 bodies at the scene.
An armed group stormed an upmarket shopping mall in the Kenyan capital Nairobi Saturday, killing at least three people and sparking a fierce gun battle, police said.
Police said they had surrounded the Westgate mall, which is popular with wealthy Kenyans and expatriates, and urged residents to stay away from the area.
The motive of the attack was not immediately clear, but Kenyan media said the attackers may have been either armed robbers or "terrorists".
AFP reporters at the scene said the surrounding area had been sealed off.
"There's an incident at Westgate and we're urging the public to keep off the area," Inspector General of Police David Kimaiyo said.
"Our officers are on the ground carrying out an evacuation of those inside as they search for the attackers who are said to be inside," he said.
"The attackers have so far injured four people. We will provide you with regular updates as we try to save the situation."
Another police official said: "Officers are approaching the situation with caution because there are innocent civilians inside."
"We have managed to evacuate some people to safety. We urge Kenyans to avoid the area as we pursue the thugs," Kenya's Interior Ministry said on Twitter.
"We have dispatched air surveillance and we confirm that they are armed criminals. We want to know who they are," said Internal Security Principal Secretary Mutea Iringo.