Trayvon marchers: 'We want an arrest. Shot in the chest"

Civil-rights organizers from the NAACP and other groups today are marching down Sanford's 13th street in the heart of one of the city's historic black neighborhoods to Sanford Police headquarters to demand the arrest of George Zimmerman in the shooting death of Trayvon Martin.

The march began at 11 a.m. at the Crooms Academy of Information Technology with an estimated 500 participatants, including people who have been bused in from across the country.

"We want an arrest. Shot in the chest," marchers are saying as they head to Sanford PD.

Several downtown streets are currently closed: 13th Street from U.S. Highway 17-92 to Lake Avenue and Persimmon Street from McCracken Road to 13th Street.

Both the Rev. Al Sharpton and Rev. Jesse Jackson are attending and have made remarks about escalating the pressure on authorities to make an arrest in the case.

Meanwhile, the Florida Civil Rights Association announced today that it supports Sharpton's call for economic sanctions.

This is a breaking news story. Check back for updates. or 407-420-5471