A senior Kenyan police officer has been shot dead after he opened fire at a magistrate in court in the capital, Nairobi.

The chief inspector opened fire on Makadara Principal Magistrate Monica Kivuti shortly after she made a ruling in a case reportedly involving his wife.

The officer is said to have been angered by the court's decision to cancel her bail after she had absconded.

The officer, identified as Samson Kipchirchir Kipruto, who is in charge of a police station in Londiani in western Kenya, then pulled out a gun and shot the magistrate, injuring her.

Other officers in court responded immediately, with one of them shooting the offending policeman and killing him.

In the process, three other officers were injured, a police report said.

The magistrate and the injured officers are being treated in hospital.

The judiciary said the magistrate had "cancelled the bond for an accused person who had jumped bond and had failed to offer satisfactory explanations for jumping bond".

"Immediately this decision was pronounced, a person shot at the magistrate and injured her on the hip,” it said in a statement.

It noted initial reports that indicated "that the shooter is a police officer who is married to the suspect".

The national police service said the officer was in the court for "unknown reasons".

Investigations are continuing to establish the circumstances that led to the shooting, it said.

The incident inside a courtroom has come as a shock to Kenyans.

The police have often been accused of being involved in extra-judicial killings but no such incident has been reported inside court.

The judiciary has said it will enhance security measures and has assured judicial staff and other court users of their safety and security.

"As the judiciary family, we wish our colleague a quick recovery. We also send our condolences to the family of the officer who lost his life in this unfortunate incident,” said chief registrar of the judiciary Winfridah Mokaya.