The two police officers were shot around midnight on Wednesday as demonstrators were gathered outside the Ferguson Police Department just hours after the local police chief, Thomas Jackson, announced his resignation, a US newspaper said on Thursday.

A St. Louis Country Police Department officials said two county officers were shot.

The St. Louis Post-Dispatch newspaper said police officials were not able to provide details on the officers' injuries. The KSDK radio station reported the officers were taken to a local hospital.

Ferguson last year became the focal point of nationwide protests against alleged racial discrimination by police following the shooting of unarmed black teenager Michael Brown by white Ferguson police officer Darren Wilson on August 9, 2014.

Jackson became the latest of six officials to step down after a US Justice Department report found widespread racial bias in the Ferguson police department, along with a court system that it accused of disproportionately arresting black residents to increase city revenue.

The report however cleared Wilson of civil rights charges. He has since left the police department.

tj/sms (AP, Reuters)