Warning signs were posted today after a lifeguard spotted a shark in waters off Chun's Reef on the North Shore.

The shark was seen shortly after noon and the signs were immediately put up on the beach, said Bryan Cheplic, spokesman for the city Emergency Services Department. Cheplic said the lifeguards were unable to determine the size or type of shark.

The signs will remain up through today and lifeguards will reassess the situation tomorrow to determine whether to keep the signs posted.

There were no reports of injuries or incidents involving the shark.