Federal officials have ordered the Massachusetts Bay Transportation Authority to undertake immediate safety measures, citing a "lax safety culture" and the agency's failure to address problems that have endangered riders and operators.

The unusual move comes after Federal Transit Administration officials said they held meetings with the MBTA and the Department of Public Utilities earlier this year, urging the agencies to "raise the bar on safety." Four more major incidents followed, including the April death of a man who was dragged to death exiting a train.

"To ensure the continued safety of MBTA employees and the passengers they serve, there are a range of issues all of which need immediate remedy," FTA Associate Administrator Paul Kincaid announced at a press conference Wednesday.

Joe Pesaturo, a spokesman for the MBTA, said the agency is fully engaged with the FTA's orders and developing immediate and long-term mitigation measures to address the FTA's concerns.

"[The MBTA is] advancing safety-related objectives with an unprecedented $8 billion in infrastructure and vehicle investments over the past five years," he wrote in an email. "The MBTA is working collaboratively with the FTA to make the T a transit industry leader in safety and reliability."

The Department of Public Utilities, the state agency overseeing the MBTA, did not immediately comment.

The FTA is in the process of a Safety Management Inspection of the MBTA and Department of Public Utilitites due to problems with passenger safety, derailments, collisions and other issues. Officials said during the inspection process, they identified concerns requiring immediate attention, such as inadequate staffing at the MBTA operations control center —where dispatchers are located — and a lack of written procedures for safety processes and training.

"Not having written rules leads to a lack of understanding of what is required, as well as a lack of safety culture throughout the agency that sets the stage for safety lapses," Kincaid said, citing a recent incident when two trains broke loose in the MBTA maintenance yard.

"These runaway train incidents are serious. They resulted in injuries to workers," he said. "The combination of inadequate procedures and staffing and a safety culture where others look away when individuals do not follow basic safety rules create circumstances that result in unacceptable and entirely avoidable incidents."

The FTA said it found problems with critically delayed maintenance and a growing backlog of track and systems upkeep. The FTA also cited lapses in employee safety certification, calling it an especially concerning problem because "a large number of workers who operate trains are not receiving adequate training to understand key safety rules."

Thirty-nine-year-old Robinson Lalin was dragged to his death at the Broadway station in April when he attempted to exit a Red Line train car as the doors were closing. His right arm was trapped in the door, and the train pulled him more than 100 feet and onto the tracks. An investigation by the National Transportation Safety Board found that a faulty local door control system caused the door not to release as it should when obstructed.

The MBTA found that the problem was due to a "short circuit," inspected its fleet, and determined it was not a problem in other train cars. Experts have criticized the incident as avoidable, saying it is typically a driver's responsibility to ensure that riders have cleared the train before leaving a station.

According to news reports, other MBTA incidents include a Red Line train derailed in South Boston in September, and an escalator malfunction at the Back Bay station the same month that injured nine people. Last year, Boston University professor David Jones died in September when he fell through a rusted staircase at the JFK/UMass stop that had been closed off and unattended for at least a year, according to news reports.

The MBTA's Pesaturo said the agency will share its plans with the FTA in the coming days and weeks.

Kincaid, the FTA spokesman, said each safety finding announced on Wednesday comes with a time frame for expected improvement. He also said the FTA's broader safety investigation will result in a full report in August.