New York City’s firefighting unions are steaming over a proposal to close 20 fire companies as a budget-cutting measure.

Members of unions representing firefighters and fire officers marched across the Brooklyn Bridge on Friday. After that, thousands of firefighters and their supporters rallied near City Hall.

Mayor Michael Bloomberg has defended the proposal, noting that response times and fire deaths are at a new low. He says sacrifices have to be made somewhere.

The city has about a month to finalize its budget.