A coalition of environmental groups on Monday said the Senate shouldn't act on President Trump's nominations to FERC pending investigations into possible Russian ties to the 2016 Trump campaign and the regulatory panel "misusing its authority regarding the approval process for pipelines."

In a letter reportedly sent Monday to Senate Energy and Natural Resources Chairman Lisa Murkowski (R-AK), Ranking Member Maria Cantwell (D-WA) and other members of the committee, the quintet of environmental groups attempted to tie any hearings on Federal Energy Regulatory Commission nominees to the ongoing controversy about possible Russian ties to Trump's presidential campaign.

"President Trump's unknown personal and professional ties with foreign leaders and foreign corporations raise serious and legitimate concerns for those he would seek to install in these highly consequential positions," according to the letter, which was signed by representatives of the Delaware Riverkeeper Network, Beyond Extreme Energy, Berks Gas Truth, Green America, and FERC Vacancies Campaign. "FERC's role in protecting the U.S. energy grid is essential to our national security...

"It is imperative that the Senate oppose advancing, and certainly take no steps to expedite, confirmation of the President's nominees to FERC." Instead, they said, the Senate should prioritize holding hearings "into the abuses of power and law already experienced at the hands of FERC, in order to identify and secure needed reforms."

Last week, the White House announced that President Trumpwill nominate Neil Chatterjee and Robert Powelson to FERC, with each to complete the incomplete terms of former commissioners, in a move that would restore a quorum at the regulatory panel.

Trump said he intends to nominate Chatterjee, a longtime energy policy adviser to Senate Majority Leader Mitch McConnell (R-KY), for the term expiring June 30, 2021, that was previously held by Tony Clark, who left FERC last September. Powelson, a member of the Pennsylvania Public Utility Commission, will be nominated for a term expiring June 30, 2020, that was previously held by Philip Moeller, who left FERC in October 2015. Both men had previously been reported as potential candidates for FERC. Their nominations will need the approval of the Senate Energy and Natural Resources Committee and the full Senate before they can take their seats at FERC, a process that could take several months.

The nominations came less than a week after Murkowski and Cantwell expressed their frustration at the continuing lack of a quorum at FERC.

"I welcome the president's announcement of two well-qualified nominees and look forward to restoring FERC’s quorum as soon as possible," Murkowski said Wednesday. "Neil will bring expertise and an ability to work with diverse groups of decision makers, while Rob has cultivated a reputation as a leader on the utility commission of a major energy producing and consuming state. We will announce a hearing to review their nominations as soon as we receive all relevant paperwork, and seek to confirm them as expeditiously as possible."

There are currently three empty seats at FERC and the expected exit of Colette Honorable at the end of June will leave the ostensibly five-member panel with a single member -- Acting Chairman Cheryl LaFleur.

Last March, Maya K. van Rossum, leader of the Delaware Riverkeeper Network and a signatory of Monday’s letter, was part of a coalition led by controversial Gasland documentarian Josh Fox thatlaunched a campaign to oppose efforts to re-establish a quorum at FERC.