A Saudi-led military coalition said it will temporarily close all air, land and sea ports to Yemen to stem the flow of arms to Houthi rebels from Iran, said a statement on Monday on state news agency SPA.
The move follows the interception of a missile fired towards Riyadh on Saturday which the coalition has described as a "dangerous escalation" by the Iran-allied Houthi militia which controls large parts of Yemen.
The coalition and US President Donald Trump have both blamed Iran for the attack, but the head of Iran's Revolutionary Guards denied the accusations on Sunday, rejecting Trump's remarks as "slanders".
The ballistic missile was intercepted by Saudi Arabia's air defences and brought down near Riyadh airport without causing any casualties.
The coalition has been targeting the Houthis since they seized parts of the country in 2015 including the capital Sanaa, forcing President Abd-Rabbu Mansour Hadi to flee and seek help from neighbouring Saudi Arabia.
"The Coalition Forces Command decided to temporarily close all Yemeni air, sea and land ports," the statement on SPA said, adding that aid workers and humanitarian supplies would continue to be able to access and exit Yemen.
The United Nations and international aid organisations have repeatedly criticised the coalition for blocking aid access, especially to the rebel-held north.
The civil war has killed more than 10,000 people and triggered a severe humanitarian crisis in one of the Arab world's poorest nations. More than half a million Yemenis have been infected with cholera and some seven million are on the brink of famine, according to the United Nations.
On Sunday a suicide car bomber blew himself up at a security checkpoint in the southern port city of Aden, killing 15 people and wounding at least 20, residents and a security official said. Aden is the interim headquarters of Yemen's internationally-recognised government.