Tropical Storm Isaac has been upgraded to hurricane level as it smashed into the Louisiana coast.

Lashing the coastal region with winds up to a speed of 80mph (130km/h), Hurricane Isaac was heading toward New Orleans, the city which was devastated seven years ago by Hurricane Katrina. Isaac was likely to weaken during its course, the National Hurricane Centre forecast.

Thousands of people were without power supply in Louisiana.

Although the latest hurricane is not as devastating as Katrina, it has the potential to cause huge floods and high winds. This will also be the litmus test for the multi-billion dollar flood defence mechanisms which are put in place in New Orleans.

After the disaster caused by Katrina, miles of levees and flood walls have been erected at a cost of $14.5 billion (£9.1 billion).

Authorities in the states say they are much prepared for the situation after the 2005 catastrophe.

US President Barack Obama has asked the people who are in the path of Hurricane Isaac to take precautionary measures.

"I want to encourage all residents of the Gulf Coast to listen to your local officials and follow their directions - including if they tell you to evacuate.

Now is not the time to tempt fate. Now is not the time to dismiss official warnings. You need to take this seriously," said Obama.

While thousands of people have left the area, many others stayed behind closed doors as there was no mandatory evacuation in place.

Assuring the people that New Orleans would be secure, Mayor Mitch Landrieu said, "We will not have a Katrina-like event. Do not let this storm lull you into complacency. People may be getting bored. It's better to be bored than to get hurt."

Stating that the city's airport was closed, Landrieu said, "We're in the heart of this fight. We are in the hunker-down phase."

US National Guard troops are also deployed in the city to prevent any looting.

Nearby states including Mississippi, Alabama are also kept in high alert for rainfall.

Keegan plays with his dog Scout as mother Ybonne supervises in flooded area as Hurricane Isaac approaches New OrleansReuters
Handout of NOAA satellite image of Tropical Storm Isaac in the Gulf of MexicoReuters
Bar owner closes the shutters of his bar, closing it down early as Hurricane Isaac approaches in New OrleansReuters
Dark clouds are seen over the Mississippi River as Hurricane Isaac approaches New OrleansReuters
Louisiana National Guard humvee drives down Bourbon Street as Hurricane Isaac approaches New OrleansReuters
New Orleans resident Bob Holloway photographs a flooded area outside of the levee system along the shores of Lake Pontchartrain as Hurricane Isaac approaches New Orleans, LouisianaReuters
Blake Noblin paddles back to shore after helping his father Jeff Noblin gather boards from a neighbor's pier on East Beach as Hurricane Isaac approaches Ocean SpringsReuters
A New Orleans resident and her child run for cover past an open French Quarter bar as Hurricane Isaac approaches New Orleans, LouisianaReuters
The storm surge washes up to Beach Blvd as Hurricane Isaac approaches BiloxiReuters
A car makes its way through flood water along Beach Blvd as Hurricane Isaac approaches BiloxiReuters
Dr. Elberta Jackson prays in her cot at the Belle Chase Auditorium shelter as Hurricane Isaac bears down on the Louisiana coast in Belle Chasse, LouisianaReuters
A lone cyclist rides down an empty Bourbon Street in the French Quarter as Hurricane Isaac approaches in New OrleansReuters