Tasnim� US State Department Spokeswoman Heather Nauert raised doubts about reports that Iran provided missiles to Houthi fighters in Yemen, noting that Washington does not have �full determination on who is responsible for that�.

�Well, in terms of what happened, in terms of a launch into Saudi Arabia that is a situation that we�re continuing to assess right now. We don�t have a full determination on who is responsible for that,� Nauert told reporters on Tuesday, according to the official website of the US Department of State.

Earlier, Saudi Crown Prince Mohammed bin Salman alleged that Iran was involved in supplying weapons to the Houthis, which he said �is a direct military aggression� by Iran against Saudi Arabia.

The Houthi movement fired a long-range missile at the King Khalid International Airport in northeastern Riyadh on Saturday.

In response, Iranian Foreign Minister Mohammad Javad Zarif dismissed as �false and dangerous� accusations by Saudi Arabia's crown prince.

Zarif rejected bin Salman's claims in a phone call with British Foreign Secretary Boris Johnson on Tuesday.

The top Iranian diplomat pointed to Saudi Arabia�s acts of provocation in the Middle East, saying that the kingdom�s accusations were contrary to international law and the United Nations Charter.