A teachers' union in Kenya has threatened to evacuate teachers out of an area where three teachers were killed on Monday morning if the government does not improve security.

The deadly attack happened in Kamuthe in Garissa county. A telecommunications mast and a police camp were also targeted.

The teachers were not from the area and the Secretary-General of Kenya National Union Teachers (Knut) Wilson Sossion is quoted in the Standard newspaper as saying that deploying teachers from the rest of Kenya to work in the region near the attack "was not the right thing at all".

The Kenyan government has promised to restore security after the threat, the Daily Nation newspaper reports.

No-one has said they carried out the attack but the Islamist militants al-Shabab have been active in the area.

Six suspected al-Shabab attacks have taken place in Kenya in just over a month, including one on a military base that left three American military personnel dead.

Al-Shabab researcher and policy advisor Abdullahi Halakhe told BBC Newsday that the group is creating a potential conflict between the locals and government workers who are not necessarily from the region.