The two met at the Munich Security conference amid tough rhetoric between President Trump and Iran's leadership. Murphy claimed he told Foreign Minister Mohammad Javad Zarif that Congress is also responsible for setting U.S. foreign policy.
"Many of us have met w Zarif over the years, under Obama and Trump," Murphy tweeted. "So though no one in Congress can negotiate with Zarif or carry official U.S. government messages, there is value in having a dialogue."
According to his tweets, Murphy also urged Zarif to control any proxies that might attack U.S. forces, as well as release American citizens unlawfully detained in the nation.
Murphy's tweets confirmed an earlier report that Murphy and other Democratic senators held a secret meeting with Zarif. It's unclear which other senators were involved.
In a Medium post, Murphy expanded on his meeting and clarified that he wasn't trying to sidestep the administration's foreign policy.
"I don’t know whether my visit with Zarif will make a difference. I’m not the President or the Secretary of State — I’m just a rank and file U.S. Senator. I cannot conduct diplomacy on behalf of the whole of the U.S. government, and I don’t pretend to be in a position to do so," Murphy wrote.
"But if Trump isn’t going to talk to Iran, then someone should. And Congress is a co-equal branch of government, responsible along with the Executive for setting foreign policy. A lack of dialogue leaves nations guessing about their enemy’s intentions, and guessing wrong can lead to catastrophic mistakes."
Murphy's chamber recently voted on a war powers resolution aimed at reining in Trump's actions against Iran. The resolution received a majority vote but ultimately failed to garner the two-thirds majority needed to overcome Trump's veto.
The meeting came as the Trump administration seeks to increasingly isolate Iran through the re-imposition of sanctions under its “maximum pressure campaign” on the Islamic republic.
Murphy has been a harsh critic of the administration’s policy toward Iran and said in a Medium post that he had raised the U.S. airstrike that killed a top Iranian general in Iraq and told Zarif that despite differences, Congress and the administration are united in sending a message that any Iran-backed attack on American troops in Iraq would be “an unacceptable escalation.”
The senator also said he had raised Iran’s support for Shiite Houthi rebels in Yemen and Americans held prisoner in Iran.
The Associated Press contributed to this report.