(*This post has been updated to include comment from Wolf administration spokesman J.J. Abbott)

Maryland’s Republican governor on Thursday slammed Pennsylvania’s clean water efforts, accusing its nearest neighbor of not living up to its responsibility to take care of the Chesapeake Bay.

Gov. Larry Hogan lodged those concerns in a sternly worded letter to Pennsylvania Gov. Tom Wolf and U.S. Environmental Protection Agency Administrator Andrew Wheeler, where he charged that Pennsylvania’s plan to contribute to the bay cleanup “falls far short” of what’s needed to keep the regional waterway healthy, and that Maryland “continues to have alarming concerns regarding [the state’s] progress on clean water.”

Hogan, who chairs the interstate Chesapeake Executive Council, urged Wheeler, a Trump administration appointee, to hold such upstream states as Pennsylvania “accountable for meeting Bay restoration goals” and to “take responsibility for pollution that pours into the Chesapeake Bay,” Hogan’s office said in a statement.

“With the recent release of the final Watershed Implementation Plans (WIP) to restore the Chesapeake Bay by 2025, Maryland continues to have alarming concerns regarding Pennsylvania’s progress on clean water,” Hogan’s letter reads, in part. “The Commonwealth of Pennsylvania’s final [plan] falls far short of the federally established nitrogen goal by only achieving 73 percent of the required reduction. Pennsylvania’s plan also includes a troubling funding gap of over $300 million annually.”

In a statement, Wolf’s spokesman, J.J. Abbott, hit back at Hogan’s criticisms, saying the state is working diligently to meet its obligations.

“Unlike Maryland, Pennsylvania doesn’t generate millions of dollars from tourism on the Chesapeake Bay and can’t use those resources, at the moment, to improve water quality,” Abbott said. “If any entity in Maryland is interested in diverting funds to Pennsylvania to bolster our efforts, we would gladly accept them. Pennsylvania is committed to having projects and practices in place by 2025 to attain our goals and meet our requirements in full.”

The interstate council, which includes six states and Washington, D.C., is slated to meet next week in Oxon Hill, Md., to discuss a host of issues, including those watershed implementation plans.

In a scathing report released in May, the Chesapeake Bay Foundation said Pennsylvania’s efforts to reduce the flow of pollution into the Chesapeake Bay lag far behind its neighbors, and the state could face action from federal regulators if it doesn’t clean up its act.

In its report, the bay foundation said that poor planning and a lack of funding have derailed the Keystone State’s efforts to reduce agricultural runoff and stormwater pollution into the bay.

In a statement issued Thursday, the bay foundation’s president, William Baker, welcomed Hogan’s actions.

“I commend Gov. Hogan for pushing the EPA Administrator and the Governor of Pennsylvania to fix and fund the Commonwealth’s deficient plan,” Baker said. “Pennsylvania remains the broken link in the Bay cleanup chain. Pennsylvania’s Legislature and Governor have repeatedly failed to fully invest in pollution reduction. In addition, EPA is not using its oversight powers to hold the Commonwealth accountable.”

Half of Pennsylvania is located in the Chesapeake Bay watershed, according to the state Department of Environmental Protection. The Susquehanna River is the single largest tributary to the bay, providing half of its total freshwater flow.

The DEP acknowledges on its website that “the water quality of the Chesapeake Bay cannot be restored without Pennsylvania’s support.”

In his letter to Wolf and the EPA, Hogan said he’d “repeatedly offered to help Pennsylvania rally the necessary financial and regulatory support to fully achieve our shared goals.”

“We urgently need a more complete and comprehensive commitment from Pennsylvania, as well as a clear and robust demonstration from the Environmental Protection Agency that appropriate oversight powers will be used to maintain our momentum.”

In another direct jab, Hogan added that his administration had already submitted its cleanup plan, and that it “continues to lead on environmental conservation in the region, with a focus on the watershed, by committing a record $5 billion toward wide-ranging Bay restoration initiatives.”

In his statement, Wolf administration spokesman Abbott said the state Department of Environmental Protection does plan to participate in a requested briefing with its Maryland counterparts, adding that “We look forward to educating Maryland officials more about the work being done to meet these goals.”

The state has made “great strides” at improving water quality in the bay’s watershed, by “investing in best practices and working collaboratively with our conservation and agriculture sectors. We’re addressing an enormous area, spanning over 15,000 miles of impaired streams, 33,000 farms, and 350 municipalities.”

But for the cleanup to be truly successful, the state’s efforts need to be complimented at the local level, and Pennsylvania’s cleanup plan “presents a framework and actions for that support,” Abbott said.

In addition, the state’s recently approved $23.1 million “Pennsylvania Farm Bill,” includes new and expanded conservation funding, with priority given to counties in the watershed, Abbott said, adding that Wolf’s $4.5 billion Restore Pennsylvania plan also invests in flood mitigation and green infrastructure.