A Kenyan military spokesman apologised Thursday for a "misleading tweet" he posted the previous day linking to pictures of a man being stoned to death by Somali Islamists.

Kenya in mid-October rolled tanks into Somalia, in order, it said, to fight the Shebab Islamists it blames for a spate of kidnappings on Kenyan soil.

The spokesman, Emmanuel Chirchir, indicated in his tweet that the victim was executed on Tuesday. But bloggers and his followers on Twitter pointed out the pictures date back to 2009.

"We acknowledge the tweet upload error, its reprint in our local press and regret the embarrassment caused across all our publics," Major Chirchir said in a statement titled "Sorry for misleading you."

The photos posted by Chirchir were subsequently published by two Kenyan dailies. They showed a man buried up to his neck, his face bloodied and caved in by stoning.

"The post was accompanied by photos published in an execution story carried out by another media house in 2009," Chirchir said Thursday.

The Major said his error should not lead people to doubt the credibility of the updates the army gives on its intervention in Somalia, termed Operation Linda Nchi.

"We have endeavored to give authentic information to the public on Operation Linda Nchi and we shall continue to do so. The tweet error should not be used as a reflection of our credibility especially on operational updates in the forum," he said.

Chirchir is known for his exchanges with an individual posting tweets on the account of the Shebab.