A large shark spotted off Nickerson Beach once again closed several Town of Hempstead beaches Tuesday.

The seven-foot shark was spotted by a town lifeguard Tuesday afternoon, which caused a "red-flag" closure of all beaches from Point Lookout Civic Beach and Lido West Town Park.

There have been more than a dozen shark sightings off of Long Island in recent weeks.

Hempstead Town Supervisor Don Clavin says more than six of the shark sightings have been bull sharks, which he called "very dangerous."

MORE: More shark sightings reported off LI's South Shore