The United States is reportedly set to unveil what it says is evidence of Iran giving missiles to Houthi rebels in Yemen.

Nikki Haley, the US Ambassador tot he United Nations, was set to show in Washington parts of a short-range ballistic missile launched by Houthi rebels into Saudi Arabia, NBC News reported.

Mrs Haley was also expected to present other examples of Iran flouting UN sanctions.

On November 4 the missile launched form Yemen was shot down by a Saudi surface-to-air missile, and came down near Riyadh airport. Saudi Arabia said it held Iran responsible, with Iran calling the claim "malicious".

The latest US move came as suspected Saudi-led airstrikes in Yemen killed at least 23 people, including prisoners, at a rebel military police camp.

The Saudi-led coalition has intensified its campaign against the Shia Houthi rebels since the killing of former Yemeni President Ali Abdullah Saleh earlier this month.

Saudi Arabia has been fighting the Iran-backed Houthis since March 2015 and has imposed a blockade on the impoverished country, allowing only occasional humanitarian access.

The stalemate war has killed more than 10,000 civilians, displaced three million, crippled Yemen's health system and pushed the Arab world's poorest country to the brink of famine.