The Canadian military is investigating a rash of fires and power outages on board several naval ships, but says preliminary indications are that there are no connections among the various incidents.

The Royal Canadian Navy has been rocked over the past two weeks by fires on two of its frigates during operations at sea near Europe. One of those frigates and a coastal-defence ship in the Pacific also experienced power outages.

Crew members were able to put out the fires quickly and restore power in each incident. A senior navy officer said there were no injuries and the problems had little impact on the vessels' missions.

Navy Capt. Trevor MacLean, chief of staff to the commander of maritime operations, said initial investigations have also failed to uncover any links among the various incidents.

There was also no indication that the problems on the two frigates, HMCS Halifax and Toronto, were connected to a series of recent technical upgrades that all 12 of the navy's frigates have undergone in the past few years, he said.

"The initial returns from those investigations are indicating that there is absolutely no relationship between these four incidents and it was really just coincidental that they happened in such a short period of time," MacLean said.

Still, MacLean acknowledged the sheer number of incidents was both unprecedented and of great concern to the navy, and said more detailed investigations will be conducted in the coming weeks.

'Highest concentration' in a long time

The problems started when a fire broke out in an engine room on HMCS Halifax on Oct. 26 as the frigate was participating in a NATO exercise off the coast of Norway. A clogged drain in the engine enclosure is believed to have been the culprit.

Three days later, HMCS Toronto lost power while patrolling off Britain. Power was restored, but a fire broke out in the engine room after the ship docked in Belfast. Indications are that a tank overflow, likely caused by the power outage, was to blame.

While HMCS Halifax escaped without significant damage and remains deployed, MacLean said HMCS Toronto is heading back to Canada and that the affected engine is "quarantined," meaning it can only be used in an emergency.

The most recent incident came Monday, when the coastal-defence ship HMCS Edmonton also lost power while involved in a U.S.-led drug-interdiction mission in the Pacific. Power was quickly restored and Edmonton later intercepted an illegal drug shipment.

"To the best of my knowledge, this is definitely the highest concentration I've seen in this short a time," MacLean said. "But the great thing we did see is we didn't skip a beat on operations."

Fires have caused significant damage — and even death — on board Canadian navy ships in the past.

Crew members on board HMCS Protecteur spent 11 desperate hours fighting a fire on their navy resupply ship in 2014, while 21 sailors on HMCS Ottawa were treated for minor injuries in 2004 after a blaze on the frigate.

And navy Lt. Chris Saunders died and three fellow crewmates were treated for serious injuries after a fire on board the submarine HMCS Chicoutimi while traversing the Atlantic in 2004.

Retired navy captain Harry Harsch said the type of fires that struck HMCS Toronto and Halifax aren't common, but do happen, and he expected a detailed investigation to identify the causes and ensure they don't happen again.

"Fire at sea, that's the one thing everyone takes very seriously," he said.