Terror organisation al-Shabaab have claimed an attack that killed 28 people on a bus in Northern Kenya.

Around 100 gunmen, who are believed to have travelled over the border in Mandera county from Somalia, took the bus off the road before separating the passengers.

It is believed they asked travellers to recite passages from the Koran, shooting dead those who were unable to prove they were practising Muslims.

A statement on a website linked to the extremist organisation said the attack was carried out in retaliation for security raids on mosques in the coastal city of Mombassa earlier this week.

Kenya's Ministry of Interior and Coordination of National Government claimed on their official account earlier today: "Attackers camp has been destroyed by KDF using helicopters and jets, many killed, operations continue."

The bus was travelling to the Kenyan capital Nairobi when it was stopped in the northern county that borders Somalia.

Around 60 people were on the bus at the time of the attack, and it is thought that among the dead are Kenyan public servants – including four police officers - who were heading to the capital for the Christmas holiday.

Mandera East deputy County Commissioner Elvis Korir said the passengers were then separated into two groups. The Somali passengers watched in horror as non-Somalis were herded away from the bus and then killed.

Mr Korir added that many details over the attack remain unclear, but the deaths underscore fears over the lack of security, especially in the remote parts of northern Kenya.

Al-Qaeda linked al-shabab recruits walk down a street in the Somalian capital, Mogadishu (Getty Images)

Abdullahi Abdirahman, the Arabiya Ward Representative, told the Daily Nation: "This place has been prone to attacks, this is not the first time the government has totally ignored us, and you can now see the how many innocent precious lives have been lost".

In early November, gunmen killed 20 police officers and two police reservists in an ambush in Turkana county in the northwest of Kenya.

The northern region of Kenya is awash with guns due to its proximity with Somalia and Ethiopia, from where the armed Oromo Liberation Front has made incursions into Kenya.

Since 2011 the Somalia-based terror group al-Shabaab, which is linked to al-Qaeda, have carried out a series of attacks in Kenya, including the Westgate Mall attack in which 67 people were killed.