Yemen's Houthis on Tuesday accused Saudi Arabia of carrying out a spate of deadly strikes that killed civilians and prison inmates, as Riyadh seeks to repel an offensive that has seen the Iran-backed group seize strategic territory.

The recent Houthi takeover of Yemen's Red Sea coast has left hundreds dead and heightened fears over global trade and shipping through the vital Bab al-Mandab strait.

It has also forced thousands to flee, with the United Nations on Tuesday forecasting the number of displaced could swell from more than 130,000 today to over 230,000 in coming months.

The gains made by the Houthis have cemented the hold of Iran and its regional allies over two key waterways in the Middle East -- Bab al-Mandab and the Strait of Hormuz -- which are major shipping arteries for global flows of energy.

Saudi Arabia, which backs Yemen's internationally recognised government, has sought to contain th...