The Pentagon is preparing to speed up the transfer of arms to help the Saudi-led coalition battling Houthi fighters in Yemen.
US Assistant Secretary of State Antony Blinken has made the pronouncement while visiting the Saudi capital, Riyadh.
"Saudi Arabia is sending a strong message to the Houthis and their allies that they cannot overrun Yemen by force. As part of that effort, we have expedited weapons deliveries, we have increased our intelligence sharing, and we have established a joint coordination planning cell in the Saudi operation centre."
Warplanes involved in the Saudi-led coalition have been pounding Shi'ite Houthi rebel positions in an attempt to keep the rebels from over-running the city of Aden.
The Houthis ousted Yemeni President Abd-Rabbo Mansour Hadi after over-running the Yemeni capital Sanaa in September.
The rebels are said to be backed by troops loyal to former Yemeni President Ali Abdullah Saleh, who was forced from power during the Arab Spring.
Meanwhile, fighting has reportedly escalated in Aden, with reports of overflowing hospitals, hijacked ambulances and bodies left in the streets.
A Red Cross attempt to send tons of medical supplies into the country has so far been thwarted by a lack of logistical support.
Around 550 people have been killed in the fighting in Yemen over the past two weeks. Some 2,000 others have been injured.
And more than 100,000 people have been displaced since the Saudi-led air strikes began two weeks ago.
