Periodically, there's a thaw in the tense relationship between Mayor Bill de Blasio and Governor Andrew Cuomo.

Sunday was NOT one of those days.

De Blasio invited the media to ride a few stops with him on the F train, as he went from his home neighborhood gym in Park Slope to a campaign event in downtown Brooklyn. And once dozens of reporters and photographers crammed on board, he excoriated the governor for the MTA's recent woes and for passing the buck to New York City. De Blasio said it's already contributed billions in funding to the agency.

"We gave them $2.5 billion two years ago, and almost 90 percent of that money is still sitting there," the mayor said. "The city has met its commitment to the MTA several times over.”

De Blasio was trying to get ahead of the story coming down the track this week: the anticipated release by the MTA of a "30-day overhaul plan." With each day bringing new subway delays, derailments and track fires, de Blasio wants to make sure MTA Chairman Joe Lhota and Governor Cuomo don't try to railroad New York City into contributing more money.

Lhota fired back, calling de Blasio's comments "totally disingenuous," because the city's payments to the state aren't "sitting around" but have been allocated to planning and construction projects that are underway and unfolding over five years.

"We know we have a problem and our job now is to fix it," Lhota said in an emailed statement. "It would best for the people of New York City if everyone stepped up and worked together in those efforts."

Governor Cuomo's office referred requests for comment to the MTA.

City Hall and the Statehouse have been pointing fingers for months at each other, with de Blasio insisting the governor is primarily responsible for the MTA, and Cuomo retorting that the city, too, shares the legal and fiscal obligations of the authority.

"I'm responsible for the NYPD. I'm responsible for the DOE. I'm responsible for the fire department. I'm responsible for the sanitation department," de Blasio said. "If something goes wrong, it's on me. If something goes right, great, I'll take credit. The governor and Chairman Lhota simply need to get in front of everyone and say, 'We're fully responsible. We have to fix the problem.'"

Technically, the city does have seats on the MTA board, but the governor appoints the chairman and has more representatives than anyone else.

After getting off the subway at Jay Street, about 10 minutes after boarding, de Blasio and his wife and entourage breezed past riders waiting on the platform, Brooklyn artist and activist Rafael Gomez Luna said he wished both leaders would say 'The Buck Stops Here.'

"I think the mayor and the governor need to work together to give us the best system," said Gomez. He said his almost daily trips to see his 90-year-old mother in northern Manhattan have regularly increased from 60 minutes to 90 or more.

"In 40 years in New York City, you see the subway get better, and you see it get worse," Gomez said. "But I've never seen anything like this."

Critics have mocked de Blasio for taking City Hall SUVs from Gracie Mansion to his Park Slope gym, rather than riding the subway as frequently as his predecessor, Mayor Michael Bloomberg.

On Sunday, De Blasio said the four-stop media circus he hosted was "not a stunt" but a way of getting the message out that it's up to the state rather than the city to fix the beleaguered subway. 

The mayor also rode the subway last Monday evening. He was spotted riding a rush hour, Queens-bound 7 train on the same day a Harlem track fire snarled nearly the entire subway system.