Two state agencies that supported and provided key approvals for state energy projects involved in a federal investigation into improper lobbying and undisclosed conflicts of interest have been subpoenaed as part of the probe, according to a source.

The state Public Service Commission and the New York State Energy Research and Development Authority were issued the subpoenas last week, the source said.

Spokespersons for both agencies said they “cannot comment on a pending investigation.” A spokesman for Preet Bharara, U.S. Attorney for the Southern District of New York, which is conducting the investigation, also declined to comment.

On April 29 federal investigators issued a subpoena to Gov. Andrew M. Cuomo’s office seeking records and documents related to a probe of one of the governor’s signature economic-development projects called the Buffalo Billion. Investigators also sought records involving a power plant proposed in the Hudson Valley by Maryland-based Competitive Power Ventures.

The Cuomo administration has launched its own investigation into the matter and suspended any regulatory dealings with CPV. Bart Schwartz, who is leading the state’s investigation, has said the state had reason to believe that “in certain programs and regulatory approvals they may have been defrauded by improper bidding and failures to disclose potential conflicts of interest by lobbyists and former state employees.”

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Among other approvals, the PSC in 2014 granted CPV a certificate of “certificate of public convenience and necessity” that provided a lightened regulatory scrutiny for a new power plant in Orange County.

In approving the request, the PSC said the project “would further various objectives identified in the most recent final State Energy Plan,” by Gov. Andrew M. Cuomo’s administration.

In addition, a NYSERDA release discussing one critical part of the Buffalo Billion revitalization points to the state’s $750 million investment in a 1.2 million-square-foot “gigafactory” for solar-panel maker SolarCity to “establish infrastructure, construct facility and purchase required equipment.”