Prison authorities have put three inmates in segregation after an officer was attacked on Monday ? the latest incident of rising violence at Westgate.

According to budget figures assaults jumped from nine to 19 last year with three of the attacks classified as major.

Prison Commissioner Hubert Dean told : "The type of inmates we are getting are more aggressive."

In the latest incident the officer sustained superficial injuries but Mr. Dean could not provide further details until the investigation was complete.

The assault occurred in the E1 wing where short-term prisoners are held.

Mr. Dean said such prisoners were more likely to be disruptive than long-termers who settle into prison life.

Asked what could be done about prison assaults he said: "I don't know. Unfortunately we only have 32 cells in the maximum security unit. We have a small segregation unit. We cannot segregate them all.

"We can only try to keep a handle on it."

He said new 15 officers were going through training but 20 were needed and another recruitment drive might be needed before the end of the year.

Officers have to deal with prison overcrowding with 217 inmates at Westgate which was built for 208. Mr. Dean said courts were locking up more civil prisoners.

"But more staff isn't going to solve the problem of violence. We need to be a little more tactful in the way we deal with people but I don't know how this one came about.

"For the most part inmates are relatively co-operative.

"Even though they could probably do whatever they want, whenever they want they seem to comply in most situations.

"Throwing more staff at it will not be the answer and may escalate the situation. We need to be tactful and we are going to look at that."

The budget statistics show inmate on inmate assaults have declined from 22 to nine but Mr. Dean said a lot of assaults went unreported.

"An inmate shows up with a bruise and says he walked into a door or fell down and we never get to the bottom of it."

Budget statistics show the annual cost of incarceration stands at $61,629 ? up from last year's figure of $55,792.

The recidivism rate has gone up five percent to 70 percent but Mr. Dean said the figures were misleading as they recorded civil and traffic offences which amounted to 29 percent of that figure.

"Without that it is 41 percent. That is a more manageable figure."