PORTLAND — Bath Iron Works in the last two weeks handed layoff notices to 53 welders and shipfitters, more than half of whom were hired this year, according to a union official.

“At the beginning of the year, they talked about hiring 600 and then 250 or 200 for the next few years after that,” said Jay Wadleigh, president of the International Association of Machinists and Aerospace Workers Local S6. “I don’t know why the sudden shift.”

He said some workers in training also had job offers rescinded. The shipyard opened a new training facility in May.

Matt Wickenheiser, BIW spokesman, confirmed the company issued layoff notices to less than 40 employees Friday. Wadleigh said the company also laid off more than 10 welders about a week prior.

“The layoffs are due to a lack of work for those particular trades at this time, given where our ships’ units are in the production process,” Wickenheiser wrote in an email confirming the layoffs. “We hate to have to take this action, and we’ll be looking to see if we can find other jobs for some number of these workers between now and Aug. 22,” when the layoffs issued Friday are to take effect.

Wickenheiser wrote that the company has three DDG-1000 Zumwalt-class destroyers and two DDG-51 Arleigh Burke-class destroyers under construction.

Wadleigh said he was “disheartened” by the news. He said he was skeptical of the company’s statement that a lack of work led to the layoffs because of the tenure of most of the workers who received pink slips.

In total, he said 25 shipfitters and 28 welders received layoff notices during the past two weeks. Most of those were issued Friday. Of the welders, Wadleigh said 17 had started this year and 11 were hired last year. Of the shipfitters, he said 12 started this year and 13 last year.

The union represents from 3,300 to 3,400 of the company’s approximately 5,600 employees. That total employment figure is up from about 5,200 at the beginning of the year, according to Wickenheiser. The company said in early May that it plans to hire more workers to bring total employment close to 6,000.