DETROIT (Reuters) - The leader of the United Auto Workers union on Wednesday warned that job security and preventing the shift of U.S. jobs to Mexico would be top priorities in contract talks with Detroit’s automakers slated for later this year.

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“There will be no more quiet closing of plants, no more shipping jobs to Mexico and abroad without a sound,” Gary Jones said in a speech to delegates the union’s bargaining convention in Detroit. “They are on notice.”

This year’s contract talks between the UAW and General Motors Co, Ford Motor Co and Fiat Chrysler Automobiles NV are likely to be contentious, with both sides also focusing on healthcare costs and the use of temporary workers.

During the convention, the union announced an increase in the amount of money paid to members if they go on strike.

“The stakes are especially high this year,” Jones said at a press conference, adding the raise in strike pay was necessary “should the (auto) companies force us to that extreme.” He took no questions from reporters.

The auto industry is expected to hit a downturn after an unprecedented run of strong sales dating to the end of the Great Recession.

The talks follow GM’s announcement in November it will close five North American plants producing less-popular sedans.

Just last week, the last Chevrolet Cruze rolled off the line at GM’s plant in Lordstown in northeastern Ohio.

The closing has drawn a lawsuit from the United Auto Workers union and significant political blowback, including from Republican U.S. President Donald Trump - Ohio is a key state for his 2020 reelection chances.

The UAW has vowed to fight for GM to reopen Lordstown with a new vehicle.

Analysts say, however, the chances of a new product being assigned to Lordstown are slim as the facility was one of several money-losing GM plants running well below capacity.

GM Chief Executive Mary Barra has said the cuts will help the company’s long-term financial stability. The automaker predicts they will improve annual free cash flow by $6 billion by the end of 2020 - and fund new electric and self-driving vehicles.

In the talks with automakers, the union plans to look closely at new technology such as electric vehicles, namely where batteries and other components will be made and whether American workers will produce them.

“Those jobs need to be here,” UAW spokesman Brian Rothenberg told reporters.