According to the Massachusetts state officials, among the most recent sightings of the white sharks is the Sunday spotting of four grand whites off Chatham's coast, by senior biologist Gregory Skomal - a shark expert with the state Division of Marine Fisheries.

Skomal sadi that the sharks were sighted off Monomoy Island, Massachusetts - which is a National Wildlife Refuge off the southern side of Cape Cod, and is only just one mile away from the public swimming area at Chatham's Lighthouse Beach.

As a result of these sightings, officials have imposed a 'swimming ban' at some oceanside beaches - including North Beach, Lighthouse Beach, South Beach and Hardings Beach in Chatham and Nauset Beach in Orleans. In addition, the officials have also cautioned other swimmers in the area to watch out for sharks.

Skomal said that he and his crew identified the sharks and were able to tag two of the sharks, between 8 and 10 feet long, with the help of electronic tracking devices, to track their movements.

The expert added that three sharks came within 75 yards of the seashore; and, because of their close proximity to the site of the sharks recently spotted, all the east-facing beaches in Chatham were closed till the middle of next week.