Four people are dead after a helicopter crashed near the town of Tweed in eastern Ontario on Thursday.

OPP Acting Sgt. Tina Hunt told CTV News Toronto the aircraft went down near the hamlet of Flinton, sometime before 12 p.m., approximately 70 kilometres northeast of Belleville.

A witness, Kim Clayton, told CP24 she was in her home this morning, located along Upper Flinton Road in the municipality of Tweed, where a large number of power line workers were set up when she hear a loud noise.

“At about quarter to twelve I heard a loud crash – I’d become accustomed to the (helicopter) noise over the last week and I knew it wasn’t normal – I saw other members of the crew running around.”

She said she went outside and saw power workers scrambling, and one of them shouted to her to call 911.

Emergency crews arrived, along with air force planes and the OPP.

“I knew it wasn’t good when the ambulance loaded the guys in and they didn’t leave,” Clayton said.

She said she can see from her home a fragment of the helicopter sitting on trees in the tree line.

A spokesperson said that an ORNGE air ambulance chopper was called to the scene but later told it was no longer needed.

Clayton said the power workers had been in the area for about a week and the helicopter was being used to ferry workers to remote areas off the roadway so crews could perform repairs.

“There were times when the chopper would fly right next to the (power) lines. I thought to myself he’s a really good pilot to fly that close to those lines.”

She said the weather in her area this morning was clear and sunny with a slight breeze. The helicopter had been flying earlier in the week in much worse conditions, sometimes taking off and landing every 15 minutes.

Hydro One confirmed Thursday the helicopter involved belongs to them and that all four people killed in the crash were Hydro One employees.

Company executive vice president Ferio Pugliese the crew was using the helicopter to do maintenance on a 230 kilovolt transmission line that ran through the area.

“This is not uncommon work,” he said, adding that Hydro One had eight helicopters in its fleet before this incident, spread throughout the province.

“Our primary area of focus is that we’re providing support for families those impacted – along with support for co-workers.”

He said at least one of the victims was from the Tweed area but others were from elsewhere and family members were still being contacted.

Pugliese said the company is cooperating with regulators and law enforcement who will conduct an investigation into the cause of the crash.

“We haven’t had an incident like this before in our entire history,” he said.

Energy Minister Glenn Thibeault said the government's "thoughts are with the employees affected, and our sincere condolences to the families of those lost in the crash."

The Transportation Safety Board said it sent a team of three investigators to the crash scene on Thursday afternoon.

They say the aircraft involved is an Aerospatiale AS 350, registered to Hydro One Inc.

Central Hastings OPP Const. Lisa Robson said a large number of officers from her detachment and others nearby were at scene of the crash.

A captain with the RCAF Joint Rescue Coordination Centre at CFB Trenton told CP24 a C-130 Hercules cargo plane and a helicopter were over the scene assisting ground crews with recovery efforts.

The OPP sent one of its helicopters to the scene as well.