Washington: Protests in Baltimore city of Maryland state over the death of an African American man due to injuries sustained while in police custody have resulted in arrests and clashes between police and demonstrators.

Two people were arrested for "public disorder and destruction of property", said Baltimore police on Thursday and television images showed protesters scuffling with police and surrounding a police car, Efe news agency reported.

Several roads in the Baltimore city were closed to traffic due to protests by more than a hundred people, mostly African Americans.

Demonstrators marched from city hall to a police station.

Freddie Gray was detained on April 12 before being hospitalised with a severe spinal injury which left him in a coma until his death on Sunday.

Six police officers were suspended on Monday while authorities in Baltimore determine how Gray was injured and whether or not the police officers were involved.

Baltimore Police Commissioner Anthony Batts met Gray's family on Thursday to tell them of progress with the investigation.

The case has added to existing tensions between police and the African American community.

At least four unarmed black men have died at the hands of police in the last few months at different locations across the US.