New York, Aug 31 (PTI): Several people, including the gunman, were killed today in a shootout in a New Jersey supermarket, the fourth such incident in the US in over a month.

Authorities were called to the Pathmark on Route 9 in Old Bridge at about 4 am local time, NBC reported.

A heavy police presence was visible outside the supermarket in New Jersey this morning. SWAT teams had set up a command post in the parking lot of a nearby restaurant.

Today's incident came just a week after the shooting at the Empire State Building when a "disgruntled" designer, who was sacked from an apparel company, gunned down a former co-worker and then randomly opened fire on the crowded sidewalks before he was shot dead by police.

On August 5, a gunman named Michael Wade Page had fired indiscriminately in a gurudwara in Wisconsin killing six members of the Sikh community and seriously wounding three others.

The frequent shooting rampages across the country have opened a debate on the gun laws.

After the gurudwara shooting, New York Mayor Michael Bloomberg had criticised President Barack Obama and Republican Presidential nominee Mitt Romney for avoiding the issue of gun laws, which he said were putting weapons in the hands of "dangerous people".

On July 20, a shooting massacre at a theatre in Aurora, Colorado -- where a gunman opened fire during a screening of the batman movie 'the Dark Knight Rises' -- left 12 people dead and over 50 injured.