Loud explosions and sustained gunfire echoed on Monday morning around a Nairobi shopping mall where al-Qaeda-linked gunmen killed at least 69 people and have been holding dozens hostage since Saturday.

Three explosions could be heard, according to reports, along with bursts of rapid machine-gun fire, as Kenyan security forces apparently renewed their efforts to secure the release of the hostages inside and end the deadly siege at the Kenyan capital’s upscale Westgate shopping center. In the early afternoon, thick black smoke poured from the roof of the complex and fire trucks were seen positioning in a road alongside the mall.

Kenya’s interior minister said two Islamic extremists were killed as military forces attempted to rescue hostages.

Kenya Chief of Defense forces Gen. Julius Karangi said fighters from an array of nations participated in the attack claimed by al-Shabab, a Somali group allies with al-Qaeda. ”We have an idea who these people are and they are clearly a multinational collection from all over the world,” he said.

The minister said some hostages have been released and the number of those remaining was minimal. A Kenyan military spokesman said earlier that the fate of hostages inside the mall was not clear despite earlier statements that “most” of them had been rescued.

According to the Kenyan Red Cross 63 people are still missing and they are thought to included hostages being held and those who may have been killed but are still inside the mall, AFP reported. At least 69 people have been confirmed dead, the Red Cross said.

Military helicopters circled over the mall at daybreak, when about five minutes of sustained gunfire broke out, a clear indication that at least one of the estimated 10 to 15 gunmen who attacked the mall when it was filled with shoppers Saturday was still on the loose.

A large military assault began on the mall shortly before sundown on Sunday, with one helicopter skimming very close to the roof of the shopping complex as a loud explosion rang out, far larger than any previous grenade blast or gunfire volley.

At the time, officials said the siege would soon end, that most hostages had been rescued and that security forces controlled most of the mall. But officials never said how many hostages had been rescued, and Kenya’s military spokesman on Monday was unable to provide details.

“We are yet to get confirmation from what’s happening in the building,” Col. Cyrus Oguna, a Kenyan military spokesman, told AP.

Late on Sunday, Kenya’s National Disaster Operation Centre said on Twitter that “this will end tonight. Our forces will prevail.”

Oguna said that many of the rescued hostages — who he said were mostly adults — were suffering from dehydration. An Associated Press reporter at a triage center next to the mall said no hostages ever showed up there.

As the crisis neared the 48-hour mark, video emerged taken by someone inside the mall’s main department store when the assault began. The video showed frightened and unsure shoppers crouching against a backdrop of long and loud volleys of gunfire.

Sunday’s assault came about 30 hours after 10 to 15 al-Shabab gunmen stormed the mall from two directions, throwing grenades and firing on civilians.

Loud exchanges of gunfire rang out from inside the four-story mall throughout Sunday. Kenyan troops were seen carrying in at least two rocket-propelled grenades. Al-Shabab militants reacted angrily to the helicopters on Twitter and warned that the military action was endangering hostages.

Kenyan authorities said they would do their utmost to save hostages’ lives, but no officials could say precisely how many people were being held captive. Kenya’s Red Cross said in a statement, citing police, that 49 people had been reported missing. Officials did not make an explicit link but that number could give an indication of the number of people held captive.

Kenya’s Red Cross said the death toll rose to 68 after nine bodies were recovered Sunday. More than 175 people were injured, including many children, Kenyan officials said.

Westgate Mall is at least partially owned by Israelis, and reports circulated that Israeli commandos were on the ground to assist in the response. Four restaurants inside the mall are Israeli-run or owned, including a branch of Artcaffe, which was reportedly the first location inside the mall targeted by the terrorists.

In Israel, a senior defense official said there were no Israeli forces participating in an assault, but said it was possible that Israeli advisers were providing assistance. The official, speaking on condition of anonymity because he was discussing a classified military issue, would not elaborate.

Gilad Millo, a Nairobi-based Israeli, said two Israeli men and a woman who were in the mall when the attack began were unharmed and safe.

Yariv Kedar, one of the three Israelis who was in Artcaffe at the time, told Channel 2 he “heard the gunfire getting closer” and bullets whizzed “over our heads” before he managed to escape.

“We started by hearing gunshots downstairs and outside. Later we heard them come inside. We took cover. Then we saw two gunmen wearing black turbans. I saw them shoot,” said Patrick Kuria, an employee at Artcaffe.

President Shimon Peres, in a Sunday letter to Kenyan President Uhuru Kenyatta, said, “I wish to extend my deepest condolences to the people of Kenya on the horrific terror attack in Nairobi. From the Holy Land we pray for the release of the hostages, the full recovery of the injured, and comfort for the families of the victims.”

Israel has close ties to Kenya going back many years. In recent years, Israel has identified East Africa as an area of strategic interest and stepped up ties with Kenya and other neighboring countries, due to shared threats posed by al-Qaeda and other extremist elements. In 2002, militants bombed an Israeli-owned luxury hotel near Mombasa, killing 13 people, and tried to shoot down an Israeli airliner at the same time.

Somalia’s al-Qaeda-linked rebel group, al-Shabab, claimed responsibility for the attack that specifically targeted non-Muslims, saying it was in retribution for Kenyan forces’ 2011 push into neighboring Somalia.

US Secretary of State John Kerry condemned what he called “an enormous offense against everybody’s sense of right and wrong,” and called the attackers “ruthless and completely reckless terrorists.”

Kerry, who was in New York for meetings at the United Nations, spoke Sunday with Somalia’s foreign minister and UN ambassador.

Earlier in the day, al-Shabab said on its new Twitter feed — after its previous one was shut down Saturday — that Kenyan officials were asking the hostage-takers to negotiate and offering incentives.

“We’ll not negotiate with the Kenyan govt as long as its forces are invading our country, so reap the bitter fruits of your harvest,” al-Shabab said in a tweet.

Kenyan President Kenyatta, who lost a nephew and the nephew’s fiancee in the attack, reiterated his government’s determination to continue fighting al-Shabab.

“We went as a nation into Somalia to help stabilize the country and most importantly to fight terror that had been unleashed on Kenya and the world,” said Kenyatta. “We shall not relent on the war on terror.”

Although this violent attack had succeeded, the Kenyan leader said, the country’s security forces had “neutralized” many others.

Former Kenyan Prime Minister Raila Odinga told reporters that “quite a number” of people were being held hostage in two areas of the sprawling complex, which includes stores for such retail giants as Nike, Adidas and Bose. Many hostages were believed to be in a grocery and general department store called Nakumatt.

Kenyan security officials sought to reassure the families of hostages but implied that some of those being held could be killed.

“The priority is to save as many lives as possible,” said Interior Cabinet Secretary Joseph Lenku, adding that more than 1,000 people escaped the attack inside the mall on Saturday.

“We have received a lot of messages from friendly countries, but for now it remains our operation,” Lenku said, adding that Kenyan forces controlled the mall’s security cameras.

Kenyans and foreigners were among those confirmed dead, including British, French, Canadians, Indians, a Ghanaian, a South African and a Chinese woman.

Britain’s prime minister, in confirming the deaths of three British nationals, told the country to “prepare ourselves for further bad news.”

Kofi Awoonor, a Ghanaian poet, professor and former ambassador to Brazil, Cuba and the United Nations, died after being wounded in the attack, Ghana’s presidential office confirmed. Ghana’s ministry of information said Awoonor’s son was injured and is responding to treatment.

Kenya’s presidential office said that one of the attackers was arrested on Saturday and died after suffering from bullet wounds.

The United Nations Security Council condemned the attacks and “expressed their solidarity with the people and government of Kenya” in a statement.