The men were released from jail on Tuesday, three days after gunmen believed to be Ethiopian rebels ambushed a Kenyan border patrol, killing one police officer, and a day before Kibaki left for Ethiopia, they said.

"On Tuesday, we deported the men who claimed to be Ethiopian security officers," national police spokesperson Jaspher Ombati told AFP.

The Ethiopians - who claimed to be government agents in pursuit of members of the Oromo Liberation Front (OLF), a rebel group fighting for its own state in southern Ethiopia - were arrested two weeks ago along the border, he said.

A Kenyan police official, who declined to be named, said the men had been released and sent back to Ethiopia after Addis Ababa confirmed their identities and in anticipation of Kibaki's trip which is aimed at calming the situation.

In Addis Ababa, Kibaki is to have talks with Ethiopian Prime Minister Meles Zenawi on a wide range of issues, including border security which has deteriorated in recent weeks.

Ombati said Kenyan authorities had arrested at least 40 people in connection with the latest violence along the border in which the police officer was killed and four badly wounded in a fierce clash on Saturday.

He said most of those arrested were believed to be Ethiopians who "will be charged in court very soon" and that the Kenyan government had reinforced security on the frontier where investigations into the incident continue.

Ombati could not say whether the detainees belonged to any particular group but noted that gunmen suspected to be allied with the OLF have been attacking Kenyan villages along the border for some time.

Last November, a gang from Ethiopia raided a Kenyan village near the border, killing a police officer and abducting two people.

Source: News 24