Kenyan official: Some gunmen from U.S.

Mohamed described the gunmen as “young men, about 18-19 years old.”

Meanwhile, Monday, Islamist al Shabaab fighters from Somalia held out at the Nairobi shopping center after killing at least 62 people, surrounded by Kenyan forces trying to end the siege.

President Barack Obama offered support as the raid went into its fourth day.

It remained unclear how many fighters and hostages were still cornered in Nairobi’s Westgate shopping center early today, after a series of blasts and gunfire were followed by black smoke billowing from one part of the complex Monday.

However, the Interior Ministry said on Twitter it was “in control” of the mall and believed all hostages had been freed.

Patronized by well-to-do Kenyans and expatriates, Westgate mall epitomized the African consumer bonanza that is drawing investment — from West and East — to one of the world's fastest growing regions.

“We will provide them with whatever law enforcement support that is necessary,” Obama said, calling the attack “a terrible outrage.”