NEW YORK: Nearly 300 cooling centres have been opened as temperatures across much of the US north-east soared to more than 90F (32C).

The shelters offer people without air conditioning a break from the heat at senior centres and community buildings.

Extra utility crews were on hand in case of power cuts, and Mayor Michael Bloomberg urged residents to help prevent blackouts by conserving power.

He also urged New Yorkers not to exert themselves in the sweltering conditions.