Disney (DIS) CEO Bob Iger announced the start of the company’s mass layoffs on Monday after the company last month outlined plans to cut 7,000 workers this year in an effort to slash $5.5 billion in costs, Report informs, citing foreign media.

“This week, we begin notifying employees whose positions are impacted by the company’s workforce reductions,” Iger wrote in an internal memo obtained by Yahoo Finance. “Leaders will be communicating the news directly to the first group of impacted employees over the next four days. A second, larger round of notifications will happen in April with several thousand more staff reductions.”

Iger, who said the final round of layoffs will take place before the beginning of the summer to reach the 7,000-job target, warned there will be “challenges ahead” for the employees still present at the company.