NAIROBI — The Kenyan foreign minister said Monday that ‘‘two or three’’ Americans were among the gunmen who attacked a Nairobi shopping mall over the weekend, killing at least 62 people.
Amina Mohamed, in an interview on PBS’s “NewsHour,’’ described them as ‘‘young men, about between maybe 18 and 19,’’ and of Somali or Arab origin. “That just goes to underline the global nature of the war that we’re fighting,’’ Mohamed said.
The US State Department said it was checking reports that Americans were among the attackers but had not been able to confirm them.
Hundreds of elite Kenyan troops — backed by armored personnel carriers, helicopters, planes, and security officials from Israel, France, Britain, and the United States — have amassed against the small group of Islamist militants still holed up in the mall.
But as night fell on Monday and a thick funnel of black smoke churned from the Westgate mall in central Nairobi, the militants were still their ground.
Kenya struggled to bring to a close a horrific episode that has deeply unnerved its people and its allies, which rely on the country as a cornerstone of stability in an often turbulent region.
“This will end tonight,” Kenyan officials had declared as a major rescue operation got under way on Sunday evening.
But shortly thereafter, three Kenyan commandos were shot to death at close range and several hostages were killed as Kenyan forces tried to move in on militants hiding in a dark corner of the mall, Western officials said.
When The Standard hit the stands on Monday with the headline, “The Final Assault,” the sound of gunfire and explosives was still echoing through central Nairobi, spreading even more fear among Kenyans, who have been shocked and demoralized by the events over the past three days.
According to the Kenyan government, 10 to 15 militants were involved in the attack and at least three have been killed in the tactical operations. At least 10 hostages were still being held by late Monday, the Associated Press reported.
Kenya is a crucial American partner whose security forces work closely with their Western counterparts to contain Islamist militants in the region.
Now Kenya’s capital, considered an oasis of prosperity in this part of Africa and an important base for Western embassies and businesses, has become a battleground in the conflict, and there is growing concern that this attack will not be the last.
Several witnesses said some of the ringleaders of the assault — in which masked gunmen moved methodically through the crowded mall on Saturday, killing men, women, and children — may have escaped during the initial confusion.
One witness said that an assailant quickly tore off his clothes and changed into a new outfit before running out, hands raised, blending in with a crowd of fleeing civilians.
Security officials in Nairobi said that two women, who were among the militants and who appeared to be directing other assailants during the killings, managed to escape after the initial stage of the attack.
That assertion raised fears that well-trained terrorists could be on the loose in Nairobi. Several witnesses have said that some of the militants were clearly not African and may have been from Western countries, but American officials said they could not confirm that.
Kenya’s security forces have a reputation for being lowly paid and underequipped, and they seem to have been ill-prepared for a complex hostage situation against die-hard militants.
According to several Western officials, the Kenyans initially rebuffed offers of assistance from the American government and turned instead to the Israelis, who dispatched advisers from the country’s defense forces.
On Monday afternoon, Kenyan security officials acknowledged that the effort to end the standoff was taking longer than expected but said it would be over soon.
“We are in charge of the situation, our people are safe, and hostages have been evacuated,” said Joseph Ole Lenku, Kenya’s interior cabinet secretary.
The militants holed up in the mall, with military-grade weaponry, are widely believed to be members of al-Shabab, a brutal Somali extremist group that has claimed responsibility for the attack.
But the possible presence of militants from outside of Africa — and the way the assailants have been ferociously fending off attempts to dislodge them — has raised questions.
Some Western security officials are now beginning to wonder if other terrorist groups may be involved.
“They are clearly a multinational collection,” said Julius Karangi, chief of the Kenyan general staff. “We are fighting global terrorism here.”
Al-Shabab spokesmen have said that the massacre was revenge for Kenya’s military incursion into Somalia, which began in 2011, when Kenya sent thousands of troops across the border to push back the group as part of the African Union’s effort to stabilize the country.
Three years ago, Al-Shabab also claimed credit for the coordinated bombings that killed more than 70 people in Uganda as crowds gathered to watch the World Cup, calling the attacks retribution for Uganda’s decision to send troops to Somalia.
The Israeli advisers are working closely with the Kenyan commandos inside the mall, helping plan specific tactical operations.
The American, French, and British officials are left with a more back-seat role from a command center just down the street from the mall, helping the Kenyans with the investigation of the attack and some intelligence matters, a high-ranking Kenyan official said Monday.
“There’s too much consultation going on,” said the Kenyan official, who had not been authorized to speak publicly. “This should have been a small rescue operation, not preparing for war.”