TORONTO -- It only took minutes for people to take to Twitter to lament they’d been woken up by an emergency alert that essentially told them not to do anything.

The alert, which was sent by mistake Sunday morning to phones across Ontario, notified people about an unspecified “incident” at a Toronto-area nuclear power plant.

One person complained there were no “public updates nearly 45 minutes after the Pickering emergency alert went out to everyone in Ontario you need to fix this.”

Another wrote, “you can’t undo what’s been done but to restore trust in the system, the province owes a full explanation of how this emergency tweet was sent in error and make fixes to make sure it doesn’t happen again.”

“I love that EVERYTHING IS FINE (in reassuring capitals) is trending. I'm genuinely happy that Pickering is safe,” one person tweeted. “And I'm learning far more about iodine pills than it ever occurred to me that I would.”

Twitter user Shawn McGuirk wrote, “nothing starts a cool Sunday morning like ALERT PLEASE STAND BY AND DO NOTHING, IT'S FINE, MAYBE. Also WHOOPS WE SENT THAT BY MISTAKE, GO BACK TO BED NOW.”

Another person tweeted, “I feel like this is how nuclear horror movies start! …. This is an alert of something we can’t say and there’s nothing you can do about it.”

As for how the alert was mistakenly sent, the Ministry of the Solicitor General released a statement saying the false alarm at the nuclear station occurred during a “routine training exercise” by the Provincial Emergency Operations Centre in Toronto.

The Government of Ontario said an investigation is also underway.

More than one person pointed out that had it been a real incident at a nuclear power plant people would’ve been unprepared.

“Waking up in Ontario: Suddenly the ice storm doesn't seem like such an emergency any more. We all have salt, but who had iodine and homemade Geiger counter supplies on their shopping list?” one woman tweeted.

And shortly after the initial alert -- through tweets from officials, including Ontario Power Generation -- people learned the warning had been sent by mistake.

"There is NO active nuclear situation taking place at the Pickering Nuclear Generating Station. The previous alert was issued in error. There is no danger to the public or environment. No further action is required," the follow-up emergency alert read.

And this only spurred dozens of other joking tweets from people.

One person tweeted “easy mistake guys....someone was reaching for the ‘don’t incite panic button’ but accidentally hit the ‘incite province-wide panic’ button instead.”

Many people online questioned how an emergency notification had been sent in error, with more than one person tweeting, “somebody is getting fired today.”

Even Newstalk 1010 reporter Lucas Meyer jokingly tweeted, “That’s a prettyyy prettyyyy big oops there.”