Washington DC - President Donald Trump said Sunday that Yemen's Houthis have agreed not to attack the US, despite the Iran-allied group stepping up its war against US ally Saudi Arabia, per reports.

According to Fox News reporter Trey Yingst, who often talks to Trump, the president said that Washington is "in constant communication with the Houthis and that they've agreed not to fight the United States."

Trump has made the claim before that the Houthis are holding back from attacking US forces in the region.

"The Houthis called us and they don't want to fight with us," Trump said during a visit to Ireland on September 12. "They don't want us to go after them."

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But the latest comments to Fox News came as close US ally Saudi Arabia is under growing pressure, with a missile targeting the capital Riyadh on Saturday.

The US State Department warned, "This military conflict has the potential to escalate rapidly," adding American citizens outside the Middle East should "seriously reconsider travel to and through the region."

The State Department restricted travel for American government employees to the Saudi cities of Taif and Yanbu, home to a major Red Sea oil export terminal that has previously been targeted by Houthi strikes.

The Houthis have also staged a rapid offensive inside Yemen, seizing swaths of territory from the internationally recognized government, which is backed by Saudi Arabia.

The Houthis said Sunday that Saudi Arabia launched 28 strikes in several areas of Yemen in the past 24 hours, as the pro-Iran group and the country's Riyadh-backed government clash in the revived civil war.

This month, the Houthis, who already held most of Yemen's populated areas, launched a lightning offensive to take over the country's entire Red Sea coast, giving them control over the vital Bab al-Mandab strait.

Fox News reported that Trump is in "deciding mode" on Iran, where US and Israeli forces launched a massive aerial bombing campaign on February 28 before settling into a now almost-seven-month standoff.

Yingst said Trump told him that "big things will be happening in the not so distant future" and that "Iranians better behave, and he is making this decision as to whether or not to blow up their nation."