Yemen's Houthi rebels must stop attacking and start negotiating, the US State Department said on Monday as the White House said it was alarmed at the recent waves of drones and missiles being launched at Saudi Arabia. The leaders of the Iran-backed Houthis "have to demonstrate their willingness to engage in a political process", US State Department spokesman Ned Price said. "They need to, quite simply, stop attacking and start negotiating. "Only then will we be able to make progress towards the political settlement that we're after," he said. Hours after Mr Price's comments, more drones were fired, Saudi state media reported early on Tuesday. Yemen's internationally recognised government has accused the Houthi rebels of failing to negotiate in good faith and not following through on promises it has made, even as it attends peace talks with UN envoy Martin Griffiths. Mr Price said the US believes the Houthis were behind the attacks on the kingdom. The State Department official said these attacks were unacceptable, dangerous and put civilians at risk, including Americans. White House spokeswoman Jen Psaki said that the Biden administration was alarmed by escalating attacks and that Saudi Arabia faces "genuine security threats" from Yemen's Iran-allied Houthis and elsewhere in the region. "We of course continue to work in close cooperation with the Saudis, given the threat," Ms Psaki said at the daily news briefing. The Saudi-led coalition in Yemen intercepted an armed drone on Tuesday morning launched by Yemen's Houthi rebels towards the kingdom, state media said. The attack targeted Khamis Mushait in the south. The UAE condemned the attack and renewed its solidarity with Saudi Arabia. "The continuation of these terrorist attacks by the Houthis reflects its blatant challenge to the international community and its disregard for all international laws and norms," the UAE's Foreign Ministry said in a statement. The rebels have stepped up attacks on Saudi Arabia in recent weeks, amid an offensive to seize the Yemeni government's last northern stronghold of Marib. The coalition said most of the dozen drones and missiles launched on Sunday were intercepted en route to their targets and there were no casualties or damage to property. Among the targets on Sunday were <a href="https://www.thenationalnews.com/business/energy/oil-surges-after-storage-facility-targeted-in-saudi-arabia-1.1179770">Ras Tanura Aramco oil terminal at one of the world's biggest oil ports</a> and another depot in Dhahran city, both in the east of the country. The attacks drew widespread condemnation from regional countries who said they violated international norms and laws and would affect the security and stability of global energy supplies. US Senator Tom Cotton attacked US President Joe Biden's administration for failing to do more to stop the attacks and accused Mr Biden of being lenient towards Iran. "Iran's missiles are raining down on Saudi Arabia. President Biden's policy? Lifting the terror designation on their proxy in Yemen and downgrading arm sales to the Saudis," Mr Cotton said on Twitter. Mr Cotton, a Republican, said Washington's policies are "emboldening Iranian-backed forces in the region". The State Department rolled back the US designation of the Houthi movement as a terror group that was made in the final days of Donald Trump's presidency. While the Trump administration's move caused concern among aid groups who feared it would make it more difficult to get humanitarian aid to civilians, the Biden administration's unilateral move to remove the designation without concession or talks was also questioned by experts.