Sen. Chris Murphy (D-Conn.) on Monday called for Yemen's Iranian-backed Houthis to answer a ceasefire proposal to end the fighting against government forces in the country.

The call is part of efforts to end the six-year civil war in Yemen and relieve the catastrophic human suffering by the civilian population. 

Murphy made his remarks in a briefing with reporters following a whirlwind trip to the region last week during which he met with officials in Qatar, Oman and Jordan. 

"There is an offer on the table which is significant, and the United States is willing to be active and present in those negotiations," Murphy said of the ceasefire proposal. 

The Biden administration has never confirmed if any U.S. officials have met directly with the Houthis on efforts to achieve a ceasefire. 

The administration in February reversed a decision by former President Donald Trump to label the Houthis a terrorist organization, but maintained sanctions on some of the group's most senior leaders. 

Murphy, who is a senior member of the Senate Foreign Relations Committee, said he pressed Omani officials in meetings to tell the Houthis to accept the ceasefire proposal and to abandon their ongoing assault on the government-controlled Yemeni city of Marib.  

"This is the moment for a ceasefire and we are hopeful that the Omanis will deliver that message to Houthis," Murphy continued.

The Houthis have been probing an assault on Marib, a strategic city controlled by government forces located in the mountains of a vast desert area, for nearly a year.

The city has accepted tens of thousands of internally displaced people over the course of the country's six-year civil war and international watchers have warned a Houthi offensive could trigger a mass exodus and further strain what little humanitarian support is available. 

"The ball was really in their court and the Houthis, if they persist with this offensive, will have to answer to the world for the humanitarian catastrophe that will be created," Murphy said. 

The situation in Yemen is also part of larger negotiations among the region's biggest players — Saudi Arabia and Iran, who are on opposite sides of the Yemen conflict — and efforts by the U.S. to rejoin the 2015 Joint Comprehensive Plan of Action (JCPOA) with Iran that former President Trump withdrew from in 2018. 

"I think having a dialogue with the Iranians that would come through a restart of the JCPOA would be helpful, with respect to the path forward in Yemen," Murphy said. "If you want to be working on peace in Yemen, you have to be talking to both the Saudis and the Iranians."

Reports that Iran is attending meetings with officials from Saudi Arabia in Iraq and traveling to the United Arab Emirates for diplomatic discussions signal a breakthrough in tensions between Tehran, on one side, and Gulf nations on the other. 

The easing of tensions are further adding to momentum that the U.S. and Iran are heading toward an agreement through indirect discussion toward a pathway to rejoin the JCPOA.

The senator's trip builds on efforts by President Biden's special envoy for Yemen Timothy Lenderking to craft a ceasefire with the parties, and in coordination with the United Nations Special Envoy for Yemen Martin Griffiths.

Speaking before the United Nations Security Council last month, Griffiths said a ceasefire is necessary as a step toward political negotiations on a peace settlement, but is key for the allowing crucial access to deliver humanitarian assistance and provide "a normalization of life that has all too often seemed like a cruel hope for the people of Yemen."