Marco Rubio: The United States is closely monitoring the situation between Saudi Arabia and the Houthis

US Secretary of State Marco Rubio said on Tuesday that the United States is monitoring the situation between Saudi Arabia and the Houthis "closely."

“The Houthis, in many ways, are agents and tools of the Iranians,” Rubio told reporters in Miami before departing on a trip to South America. “The United States has a very strong defensive military relationship with Saudi Arabia, and we are monitoring those events closely.”

He continued: "The matter has been going on for a while. I think there are some ground operations as well," noting that "the Yemeni forces are confronting the Houthis and obstructing some of their attempts to achieve ground progress."

His comments come after coalition forces in Yemen, led by Saudi Arabia, vowed to respond to a wave of attacks launched by Iran-backed Houthi rebels early Tuesday morning, wounding at least 73 civilians.

Rubio referred questions related to the defense aspect to the Pentagon, but added: “I do not think there will be any announcements on this matter today.”

Earlier Tuesday, a source familiar with Saudi trends told CNN on Tuesday that Saudi Arabia plans to respond to the Houthi attacks, and that it has informed its allies of its plans.

The source explained to CNN that Saudi diplomats had informed American lawmakers in August of the collapse of political channels with the Houthis and of the rebels’ plans to escalate against the kingdom, and they sought Washington’s support to confront them.

The source said, “(The Saudis) are coordinating with the US Central Command (CENTCOM) on the next steps, and they have informed the European partners about this as well,” noting that retaliation was “always the alternative plan in the event that the Houthis launch an attack.”

It is not yet clear what form this response will take or how severe it will be.

The source added that the Kingdom is also working to involve other countries - some of which feared being seen as a party to an American war against Iran - in efforts to confront the Houthis.

The source explained, “The partnerships established within the framework of the maritime alliance came in the context of efforts to prevent this from happening, as well as in preparation for this possibility,” referring to the defensive maritime alliance that was established in late July with the aim of protecting commercial navigation, energy routes, and freedom of navigation in the region.

In late July, Saudi Arabia joined the United States in launching strikes against Iranian-backed armed groups in Iraq; These groups - according to an American official - had directed attacks against the Kingdom.

At the time, the source familiar with Saudi trends told CNN that the message sent to both the Iranian-backed militias in Iraq and the Houthis in Yemen was clear and intended: “We are not seeking to pursue you, but if you force us to pursue you, we will do so, and you will not like what you will see.”