NAIROBI — Kenyan detectives have arrested nine suspects in connection with a Somali militant attack on a Nairobi hotel and office complex that killed 21 people, police said on Friday, indicating the search for possible accomplices in the raid is gathering pace.

President Uhuru Kenyatta said on Wednesday evening that a 20-hour siege had ended with security forces killing five militants who had stormed the hotel complex, forcing hundreds of people into terrifying escapes.

“The detectives are looking for a woman suspected to have ferried weapons from Kiunga through the port city of Mombasa to Nairobi,” a police official who did not wish to be named said, referring to a region near the Somali border.

On Wednesday, Inspector General of police Joseph Boinnet said they had arrested two people in connection with the attacks.

The police official did not say when the other seven were arrested.

Al-Shabaab, a Somalia-based Al-Qaeda affiliate, said it carried out the assault on the upscale dusitD2 compound over US President Donald Trump’s decision to recognize Jerusalem as Israel’s capital.

Kenya, the East African hub for multinational companies and the United Nations, became a frequent target for Al-Shabaab after Kenya sent troops into neighboring Somalia in 2011 to try to create a buffer zone along its border.

Sixteen Kenyans including a policeman, an American survivor of the Sept. 11, 2001 Al-Qaeda attacks on the United States, and a British development worker were among the dead in the hotel 14 Riverside Drive complex attack.

Images of the bloodied bodies of five attackers were broadcast across social media as Kenyatta announced the end of the siege, which echoed a 2013 Al-Shabaab assault that killed 67 people in the Westgate shopping center in the same district. — Reuters