A Kenyan police officer stationed at one of the gates of the president's official residence in the capital, Nairobi, has died after being shot with an arrow, officials have said.

Police said that on Monday morning, a 56-year-old man, armed with a bow and arrows, approached officers at the gate of the State House and was ordered to surrender. Instead, he moved forward and shot PC Ramadhan Matanka in the ribs.

The policeman was immediately taken to the hospital but died while undergoing treatment, according to a police statement.

The attack has raised questions about possible security lapses as the State House is one of Kenya's most heavily guarded locations.

PC Matanka's body is now in a mortuary, and there will be a post-mortem later.

An investigation is also underway to establish the motive behind the attack.

Local media are reporting that the dead policeman had been among those screening vehicles entering the State House.

The alleged attacker, who had reportedly disguised himself as a homeless person carrying a sack concealing the weapons, was detained following the assault.

Video footage, published by Kenyan television channel NTV later on Monday, showed a handcuffed man with visible injuries. He was in a police vehicle and was reportedly being taken to the hospital for treatment.

The man is expected to appear in court later on Tuesday, local media are reporting.

"The National Police Service condemns this heinous act and commends the officers for their swift response, which prevented further harm," police spokesperson Muchiri Nyaga said.

He sent his condolences to the family of the dead policeman, noting that the officer had "paid the ultimate price in the line of duty".