The Federal Transit Administration is demanding the CTA take immediate action to improve safety or risk losing funding.

In a letter to Governor JB Pritzker and Mayor Brandon Johnson, the FTA says the CTA has failed to keep riders and workers safe. 

The FTA letter says assaults on CTA workers have been higher than the national average for a decade, and attacks on passengers are up 150 percent in five years. 

The FTA says the CTA has failed to update its agency safety plan and has not put adequate measures in place to address what they call a years-long pattern of violence.

The funding threat was issued after a woman was set on fire on a Blue Line train last month. 

On Nov. 17, a 26-year-old woman was allegedly set on fire by 50-year-old Lawrence Reed, who had more than 70 prior arrests. He is now facing federal terrorism charges. At the time of the attack, Reed was on electronic monitoring after a Cook County judge declined to hold him in jail on an aggravated battery charge

As a result, the FTA is calling for more law enforcement on trains and buses.  

FTA demands amid funding threat

Under the order, the CTA must update its safety plan by the end of the month, submit a security enhancement plan by Dec. 15, and implement the plan by Dec.19.

Federal officials say they will monitor the CTA's progress and can withhold funds if the agency does not comply.

"FTA will conduct scheduled meetings with CTA to review its progress until such time as FTA determines that these meetings are no longer needed or may be conducted with less frequency," The letter stated. "FTA also may conduct onsite inspections and assessments to confirm implementation of required actions." 

CBS News Chicago has reached out to a CTA spokesperson for a comment. 

This is a developing story. CBS News Chicago will continue to provide updates.