By Jane Standley BBC New York correspondent

New York's Police Commissioner, Raymond Kelly, is warning that the force will shrink to its smallest size in a decade if proposed city-wide budget cuts are made.

New York has a nearly $5bn deficit and will be technically bankrupt when the fiscal year begins on 1 July.

If the new mayor, Michael Bloomberg, puts in place all the budget cuts necessary to balance New York's books, the number of officers may fall by several thousand.

There are fears that the city's crime - which has been down for several years - will start to rise again.

Early retirement

The cutback in crime in New York in recent years was the pride and joy of former mayor Rudolph Guiliani.

Rudolph Giuliani cleaned up New York's streets

He put more officers in the police force than ever before and developed the controversial "zero tolerance" style of policing.

But from the peak of nearly 41,000 officers in New York during his administration, the city now faces a shrinking in the police force, down to just over 35,000.

The new mayor is counting on $500m in help from New York State and the federal government in Washington not to have to do this.

But some fiscal analysts are doubtful that the money will be forthcoming.

An additional problem is the current high level of retirement of police officers.

Many more than usual are leaving as their pensions benefit from the unprecedented overtime most have been doing since the attack on the city on 11 September.