Texas health officials reported 663 measles cases in the state on Tuesday, accounting for the majority of cases across the U.S., which reached nearly 900 as of Friday, according to the Centers for Disease Control and Prevention.

The measles outbreak centered in northwest Texas grew to 683 cases and spread to three new counties on Friday, according to health officials. The latest update from the Texas Department of State Health Services adds 20 new cases since the agency's last update on Tuesday.

Sign up for The Brief, The Texas Tribune’s daily newsletter that keeps readers up to speed on the most essential Texas news. The number of cases reported in Texas' historic measles outbreak has risen to 683 cases in 29 counties,