Saudi authorities have claimed to have blocked more than 24,000 people trying to enter the country since Riyadh initiated air strikes against Shi'ite Houthi rebels in Yemen, local media reported.

Major General Mohammed Al Ghamdi, spokesman of the Saudi Border Guard, was quoted by Arab News as saying some 1,413 Yemenis who crossed into Saudi Arabia over the last two weeks were being cross-checked with the Interior Ministry's most wanted list, while another 24,506 people had been turned away from the border.

The UN Refugee Agency (UNHCR) said it was not immediately able to comment on the claim, not having any information on this issue.

"As a general principle borders should be open to civilians fleeing violence and conflict," UNHCR spokeswoman Ariane Rummery told IBTimes UK. "However, it is quite understandable that states will screen people crossing borders and seek to ensure the civilian nature of asylum."

BBC correspondent Kim Ghattas tweeted from the western Saudi-Yemen border crossing in Gizan that the situation there was "quiet".

Saudi Arabia launched Operation Decisive Storm to quell a Shi'ite rebellion in Yemen at the end of March.

The Sunni Kingdom put together a coalition of Arab states after the insurgents seized control of Yemen's capital Sana'a, earlier in 2015, forcing Sunni president Abed Rabbo Mansour Hadi to flee.

Riyadh and its allies have been bombing Houthi positions since 25 March, claiming the rebellion has been fuelled and supported by its rival, Iran.

Iran has denied the allegations and sent two navy vessels to the Gulf of Aden, off the southern coast of Yemen, to "safeguard naval routes for vessels in the region".

Iran's Supreme Leader Ayatollah Ali Khamenei denounced the Saudi-led air strikes as "criminal".

Meanwhile the UNHCR said more than 300 Yemeni refugees fleeing the escalating violence have arrived in the Horn of Africa's country of Djibouti.