At a press briefing in South Korea US Secretary of State John Kerry told reporters that Washington supports an extension to the “humanitarian pause” of fighting in Yemen.
"We know that the Houthis were engaged in moving some missile-launching capacity to the border and under the rules of engagement, it was always understood that if there were proactive moves by one side or another, then that would be in violation of the ceasefire agreement," Kerry said.
"Saudi Arabia, under the rules of engagement, took action. We continue to support the idea of extending the humanitarian pause, but I think under the circumstances at the moment that would be difficult."
His statements came as the Saudi-led coalition continued conducting air strikes in the Yemeni city of Aden Monday following the end of the five-day ceasefire between the coalition and Iranian backed Houthi militias.
The United Nations has called on both parties to extend the truce five more days, a move that was warmly welcomed by the Houthis.
"We welcome the call by the UN envoy to Yemen ... regarding the extension of the truce and the need to deliver humanitarian aid to citizens," Yemen's Houthi-controlled state news agency SABA quoted Brigadier General Sharaf Luqman as saying.
Earlier on Sunday, Yemeni politicians gathered in Riyadh for a three day meeting to discuss prospective peace in Yemen in which the Houthis declined to participate.
Since last Tuesday, the parties had been holding a five day long humanitarian ceasefire under the auspices of the UN.
"I am hopeful [there will be an extension]," Ould Cheikh Ahmed told reporters on the sidelines of the Riyadh conference, which Yemen’s internationally recognised President Abd-Rabbu Mansour Hadi - who later fled to Saudi Arabia - also attended.
"All my first contacts indicate that we have a chance, but I am really calling on all parties to extend this for a minimum of five days." Ahmed added.
The short-term armistice enabled the delivery of food deliveries, fuel and medical supplies to millions of Yemeni people who were badly affected by the conflict.
Yemen has been suffering from an ongoing civil war since President Abd Rabbuh Mansur Hadi was deposed through a military coup by the Houthis in February.
The Houthis and ex-army officials, who are loyal to former Yemeni president Ali Abdullah Saleh - who was also forced to resign during the Arab spring - had begun an offensive on the country’s capital Sanaa.
The Houthis later progressed to the south-western port city of Aden where the deposed president Hadi established an interim government before he fled to Saudi Arabia.
Soon after Hadi fled from Yemen, the Saudi-led operation dubbed “Decisive Storm” began on March 26 and kept up throughout April.
The Arab coalition backed its involvement with the claim that it is “defending the legitimate government” of the embattled President Hadi.
The operation has gained an international acceptance from Western governments and among Sunni Arab regional powers, along with Turkey. However Iran and Russia have objected to the intervention.
The Yemeni crisis has further strained relations between Iran and the Gulf Arab states.
The aforementioned Saudi-led coalition accuses Iran of “irredentism” over Yemen due to its support of the Houthi militias, thereby spreading “aggressiveness” in the Gulf region.
The UN human rights office has so far released a figure of 646 civilian deaths during the Saudi-led air strikes, while 300,000 people are believed to have been displaced, according to the same statistics.
Sending ground forces into Yemen has been a hotly-debated topic, since the Saudi-led aerial operation did not halt the Houthi’s advancement towards the Gulf of Aden.
Saudi Arabia and its Gulf allies have been mulling over sending ground forces, but the US have pushed the parties to come closer to a diplomatic solution as Russia and Iran object to Arab moves towards a ground military operation.