Diana Ross was arrested in Tucson in December 2002

"The public perception is that Diana Ross got away with it," said Holly Robles of the Tucson-based Pima County Mothers Against Drunk Driving group.

Ross was sentenced on Monday after entering a "no contest" plea.

She had been arrested in December 2002 after reports of a car swerving and driving on the wrong side of the road.

'Overwhelming'

Tests showed the 59-year-old soul singer was two times over the legal alcohol limit.

Ms Robles said it was "amazing" how much the case had affected the local community and she received an "overwhelming" number of phone calls from people unhappy at what they saw as lenient treatment.

Scores of Tucson residents also called government offices, news outlets and local and state advocacy groups, the Agence France Presse news agency reported.

The protestors called for residents to picket their City Hall, the recall of the sentencing judge, or public chastisement of their mayor, the report said.

'Usual sentence'

Callers to the city's court system were read a statement: "This is the usual sentencing that first-time driving while under the influence of alcohol offenders get."

Ross' lawyer said the singer would serve her term at a prison near her Los Angeles home.

The sentence will have to be served by 9 March, and she will also have to undergo at least 36 hours of alcohol abuse treatment before 9 August.

Officers at the scene of her arrest reported that her eyes were watery and bloodshot and she fell over while being questioned.