The state Security Operations Center is investigating a computer attack Sunday that targeted the state’s official government website and a site maintained by the Thirty Meter Telescope project.

A group calling itself Operation Green Rights, which purports to be affiliated with the activist hacker group Anonymous, announced the attack via social media and its own blog around 10 a.m. Hawaii time.

"TMT today was the victim of an unscrupulous denial of service attack, apparently launched by Anonymous, which caused the TMT website server to be unavailable for approximately two hours," said TMT Hawaii Community Affairs Manager Sandra Dawson in a statement released Sunday evening. "The incident is being investigated."

The state site was already back online when officials learned of the attack around 4:30 p.m.

Cindy McMillan, communications director for Gov. David Ige, said she could not confirm that the site was actually down.

Operation Green Rights posted screen shots "Unable to Connect" and "Site Offline" messages from the two targeted sites along with the heading "Anonymous with the Hawaiian natives against #TMT" and a short message: "Nothing will ever justify the destruction of ecosystems; filthy money can never replace them. Stand with the Hawaiian natives against #TMT (Thirty Meter Telescope)."

The group’s Twitter posting drew relatively minimal reaction, with 18 re-tweets and 33 "favorites."

So-called "denial of service" attacks typically bombard a server with multiple external communications requests so that the server must reset or cannot communicate normally with its intended users.

Big waves forecast for northern shores

A north swell will reach dangerous levels Monday, the National Weather Service said in issuing a high-surf advisory through 6 p.m. Tuesday.

Surf along Oahu’s North Shore will rise to 10 to 15 feet, and 6 to 9 feet along east shores.

Search goes on for fisherman

The Coast Guard and Maui County firefighters continued searching Sunday for a missing mariner after the fishing vessel he was aboard capsized about a mile west of Lanai.

The Coast Guard rescued fisherman Kenny Corder and was still searching for Ron Ingraham after receiving a mayday call at 12:12 a.m. Friday from the 34-foot fishing vessel Munchkin.

An MH-65 Dolphin helicopter crew from Barbers Point found and recovered Corder in the water at 3:20 a.m. He was transferred to Maui Memorial Hospital, where he was reportedly in good condition.

Corder reported that Ingraham was not wearing a life jacket.

The Coast Guard Cutter Kiska, a 110-foot patrol boat based in Hilo, a 45-foot response boat from Maui and a helicopter crew from Barbers Point continued the search in 15 mph wind and 3-foot seas.

As of Sunday, crews had completed 45 sorties and searched 1,874 square miles

The Maui Fire Department said it will not resume searching Monday unless there are further developments.

Lifeguards aid Iowan snorkeler

Kauai lifeguards resuscitated a 61-year-old visitor from Dubuque, Iowa, involved in a near drowning Saturday at Haena Beach.

The man had been snorkeling about 20 yards offshore when he apparently became distressed and was brought to shore by a relative.

Lifeguards performed CPR on the man until he regained consciousness and began breathing on his own.

The man was brought to Wilcox Memorial Hospital in an undisclosed condition.