NAIROBI, Kenya -- Israeli advisors were reported to be helping Kenya's government try to free hostages held by terrorist gunmen in an upscale shopping mall, after an attack that killed at least 59 people and wounded 175, but President Uhuru Kenyatta said the rescue attempt remained a domestic operation.
"For the time being, this remains an operation of the Kenyan security agencies. I thank all our international friends who have reached out to us and stood with us," Kenyatta said.
Kenyan and Israeli sources told news agencies Israelis were involved in the siege as it entered its second day, with occasional gunfire rattling out, as police and army units surrounded the Westgate shopping mall, where 10 to 15 gunmen were holed up with hostages.
"The Israelis have just entered and they are rescuing the hostages and the injured," a Kenyan security source told Agence France-Presse.
Israeli officials declined to comment on reports its commandos were participating in the siege. Several Israeli entrepreneurs own businesses at the Westgate mall, including a popular café and bakery.
Late Sunday afternoon, about five military and police helicopters flew in and circled the mall at a low height.
There was a heavy police presence at the mall, but crowds kept gathering across the road to watch and wait as the siege dragged on. Police dispersed the crowds several times.
There were fears the death toll could mount sharply after the Kenyan Red Cross Society announced Sunday that 49 people were missing and unaccounted for.
Kenyatta told journalists at a news conference that his nephew and the young man's fiancee were both killed in the siege.
"These are young, lovely people who I personally knew and loved," he said, vowing to bring the masterminds of the attack to justice. He said it was "remarkable and encouraging" Kenyan security services helped rescue about 1,000 people from the mall.
"No one should lose their lives so needlessly and so senselessly and no family should have to receive news that their loved one has been killed by a criminal bunch of cowards," he said.
"We shall punish the masterminds swiftly and very painfully," he said.
Three Britons, two French, two Canadians, a Chinese citizen, and renowned Ghanaian poet Kofi Awoonor were also among the dead.
The number of hostages wasn't known, and other civilians were believed to be hiding in the building. Several hostages managed to escape Sunday.
Kenyatta refused to comment on reports the gunmen were wearing explosive vests. He said it was believed that some of the attackers were women.
The Al Qaeda-linked Somali militant group Shabab has claimed responsibility for Saturday's attack in a series of tweets, saying it was revenge for Kenya’s push into Somalia in 2011.
"The attack at #WestGateMall is just a very tiny fraction of what Muslims in Somalia experience at the hands of Kenyan invaders," the group’s media office said in one tweet.
The group also ruled out negotiations with Kenyan authorities on the release of hostages.
Kenyatta ruled out any withdrawal of Kenyan forces from Somalia.
"We went as a nation into Somalia to help stabilize the country but most importantly to fight a war against terror. We shall not relent on the war on terror," he declared.
Kenyatta acknowledged Kenyan frustration at how long it was taking security forces to resolve the crisis but urged people to be patient and give the police and army time.
"With professionals on site, I assure Kenyans that we have as good a chance to successfully neutralize the terrorists as we can hope for."
In Jerusalem, Israeli Foreign Ministry spokesman Paul Hirschson said Israel does not comment on its security cooperation with other countries. He added it does not appear that Israel or Israelis were being specifically targeted as they have been in previous attacks in Kenya.
In 2002, terrorists bombed an Israeli-owned hotel in the resort town of Mombasa and tried unsuccessfully to shoot down a plane carrying Israeli tourists.
Since then, cooperation between the two countries has increased.
In 2012, Kenyan authorities arrested two Iranian agents in Mombasa and charged them with planning to use explosives to attack Israeli-owned resorts.
This year, Israel’s spy agency Mossad reportedly helped Kenya investigate the massive fire that heavily damaged Nairobi’s international airport.
Special correspondent Soi reported from Nairobi and Times staff writer Dixon from Johannesburg, South Africa.