The National Oceanic and Atmospheric Administration began cutting its probationary workforce on Thursday, with hundreds working at the top climate and weather forecasting agency affected by the layoffs as the Trump administration continues to cut the federal workforce to reduce spending.

The cuts could affect more than 10% of the employees at the agency, according to two sources with internal knowledge of the agency. On Thursday afternoon, the Commerce Department sent emails to hundreds of employees saying their jobs would be cut off at the end of the day. More notifications of terminations are expected on Friday.