Kenyan authorities have arrested five people suspected of preparing a terror attack in Nairobi, according to a police report seen by AFP on Sunday.

The group comprises three men – a US citizen, a Somali and their Kenyan driver – and two Somali women who were believed to be on a reconnaissance mission for an attack in the north of the capital, the report dated Saturday said.

Police received information on Friday saying that “suspected terrorists” were carrying out a surveillance operation at a pub on Kiambu Road, a spot popular for its many bars and nightclubs.

Kenyan security forces have been on high alert since the Somali al-Shabaab group, close to al-Qaeda, stepped up attacks in the east of the country this month, threatening to target more Kenyan and US interests.

On January 5, the Somali al-Shabaab group attacked Camp Simba, killing three Americans and destroying several aircraft and warning Kenya to withdraw its forces from Somalia while they still “have the chance”.

Kenya sent troops into Somalia in 2011 as part of an African Union peacekeeping mission fighting against al-Shabaab, and has seen several brutal retaliation attacks both on its troops in Somalia and civilians in Kenya.