Ocean Safety officials posted shark warning signs at Bellows beach in Waimanalo Friday afternoon.
Two sharks roughly 8 to 10 feet long were spotted about 30 to 50 yards offshore. An off-duty lifeguard spotted the sharks from shore. The lifeguard said the sharks were acting 'aggressively' and were thrashing in the water.
Ocean Safety received the call around 2:15 p.m. and lifeguards immediately cleared the water. The shark sighting was on the military side of Bellows about a mile down the beach from the City's lifeguard tower.
The signs will remain up for the rest of the day. The area will be reassessed in the morning around 9 a.m.