Late Wednesday, SEPTA said that a work action that had been planned for Thursday -- and could have delayed commutes for essential workers -- has been delayed.

KYW Newsradio's Mike DiNardo reported that the mayor had asked the two sides for more time for talks.

#BREAKING: TWU calls off its job action against @SEPTA tomorrow, after @PhillyMayor asks for time to talk with SEPTA about the union’s coronavirus concerns. pic.twitter.com/OQdyUvzTAi — Mike DeNardo (@_MikeDeNardo) April 22, 2020

Earlier in the day, SEPTA had warned riders that service could be disrupted, and possibly suspended, on Thursday because of a labor action by the largest union of transit agency employees.

"SEPTA is not clear on the details of this potential work stoppage, however, at minimum, it would likely force the suspension of bus service within the City of Philadelphia," the agency said in an email Wednesday afternoon. "SEPTA is looking at all possible options for maintaining some core services, such as limited operations on the Market-Frankford and Broad Street Lines."

The agency said more details would be made public as soon as possible.

The Transportation Workers Union Local 234, which represents hundreds of agency employees still working on buses, trolleys and trains during the coronavirus pandemic, has publicly aired grievances with SEPTA leadership during the crisis.

SEPTA did change its boarding policy for buses, requiring passengers board through rear doors and suspended on-board payments.

However, no labor actions have yet shut down the transportation system during the six-week-long crisis. TWU Local 234 President Willie Brown issued a warning in a short YouTube video to SEPTA administrators.

"I have notified SEPTA that as of Thursday, April 23, since they have not met some of our concerns when it comes to safety of our members when it comes to the coronavirus, that we will choose life over death," Brown said. "SEPTA is turning a blind eye, a deaf ear to our concerns. So stay tuned. Watch the news."

Wednesday night, a spokesperson for TWU confirmed the work action was delayed.

"Today, Mayor Kenney met with SEPTA and also with the leadership of our union regarding our requirements," a TWU spokesperson wrote.

"The mayor is sympathetic to our needs and to those who rely on us for transportation. He has asked us to postpone our actions planned for Thursday and to grant him a few days to work with SEPTA to raise standards to a level our members would find acceptable.As a sign of good faith, we are postponing our job action, but this is not as SEPTA management said in a message this evening 'a cancellation.'"

The spokesperson also wrote the union would take action "very shortly" if there was no improvement.

At least four SEPTA employees have died: three maintenance workers and a Regional Rail conductor. Ridership has plummeted to nearly non-existent levels, and tempers over policies like face mask requirements have occasionally led to police-involved incidents on the transit system.