The comments came as the Saudi-Emirati-led military coalition deployed more than 10,000 new troops towards a vital rebel-held port city in the run-up to a new assault.
James Mattis, the Pentagon chief, said the US had been watching the conflict "for long enough", adding he believes Saudi Arabia and the United Arab Emirates - who are in a US-backed coalition fighting Houthi rebels - are ready for talks.
"We have got to move toward a peace effort here, and we can't say we are going to do it sometime in the future," Mattis said at the US Institute of Peace in Washington.
"We need to be doing this in the next 30 days."
US Secretary of State Mike Pompeo later called on the Saudi-Emirati coalition to stop air attacks in populated areas in Yemen. Pompeo said the "time is now for the cessation of hostilities" in the war-plagued country.
Mattis said the United States is calling for all factions to meet United Nations Special Envoy Martin Griffiths in Sweden in November and "come to a solution".
The UN says Yemen could become the worst humanitarian catastrophe the world has seen in 100 years.
The United States has faced fierce international criticism for its role in supporting the Saudi-led coalition, especially after a series of air attacks killed scores of civilians. The US Air Force has been aiding the Saudi-led coalition’s aerial campaign agaonst Yemeni people..