Union officials say General Motors is cutting 625 jobs at its assembly plant near London, Ont. by the end of July, in a move to shift more production to Mexico.

Mike Van Boekel, spokesman for Unifor Local 88, says the layoffs will take effect in July at the CAMI Assembly plant in Ingersoll, Ont., which currently employs 2,800 Unifor members. The plant produces the Chevrolet Equinox and GMC Terrain mid-sized sport utility vehicles.

The news came as a surprise for auto workers. For months, the plant has been on a hiring spree, cranking out vehicles six days a week.

“I am not sure what happened between the beginning of January and now,” Unifor Local 88 president Dan Borthwick told CTV News.

Although GM recently announced it was shifting production of the GMC Terrain to Mexico, Unifor's national president says workers were led to believe increased production of the Chevrolet Equinox would eliminate the need for job cuts.

“There wasn’t going to be any anticipated layoffs,” Unifor national president Jerry Dias told CTV News Channel on Friday. “Now we know that is not correct.”

GM Canada says it gave Unifor advance notification of how product changeovers would affect workers at three Ontario plants. A spokesperson said the announcement related only to “an employment impact at CAMI due to the changeover of older model Equinoxes to the next-generation Equinox.”

The CAMI plant was not part of the Detroit Three negotiations this past fall, when Unifor was able to secure more than $1.5 billion in investment for production and jobs.

Dias said GM’s decision to eliminate Canadian jobs “reeks of corporate greed” and warns “this is the nasty side of NAFTA.”

He has repeatedly called for a renegotiation of the longstanding trilateral trade deal, and praised U.S. President Donald Trump for his tough stance on the U.S. trade imbalance with Mexico.

“This is a prime example of why it needs to happen,” Dias said of a NAFTA overhaul. “The trade deals that Canada has signed have really been about corporate rights instead of workers’ rights… This is 600 jobs. This is 600 families … You are looking at a massive hit to the community of Ingersoll and London.”

The layoffs are expected to send shockwaves through communities surrounding the Ingersoll plant. The majority of workers commute to work from nearby towns, including Windsor, Sarnia and London.

A local community business centre has serious concerns that the corporate decision could have a ripple effect for other local businesses.

“It will be devastating,” said the owner of Louie’s Pizzeria, who said that auto workers represent at least 20 per cent of his business. “We will in turn have to let people go, and it’ll be a landslide.”

Ingersoll Mayor Ted Comiskey said there is still time to prepare for the July layoffs, but he hopes that the decision could be reversed.

“Hopefully by July some plans have come into play that will reduce the numbers or eliminate them,” Comiskey said.

Industry experts worry that this could be the start of further Canadian job losses in the auto industry. U.S. President Donald Trump has promised to rip up NAFTA as part of his “America First” policy and has met with heads of GM, Ford and Fiat Chrysler to convince the companies to build more vehicles in the U.S. And for every auto industry job lost in Canada, Unifor estimates that seven others in the auto industry as a whole are also let go.

"If the U.S. starts to consolidate in the U.S., the danger is it will negatively impact Canada as well,” auto industry expert Charlotte Yates told CTV News.

While the prime minister has announced that he would be open to changing NAFTA, today, the Economic Development minister said he was caught off-guard by GM’s announcement. He said that the government will attempt to attract business to the country by taking the high road.

“We don't want to be in a race to the bottom,” Minister of Innovation, Science, and Economic Development Navdeep Bains said on Friday. “We don't want to be the lowest cost jurisdiction -- we want to be a jurisdiction that builds smart products."

With a report from CTV’s Peter Akman and files from The Canadian Press