The Houthi rebels' threat to blockade Saudi Arabia has the potential to widen the Iran war and further disrupt global oil supplies and international trade.

The Iran-backed rebels say they have closed the Bab el-Mandeb Strait to Saudi-linked shipping in retaliation for the kingdom's blockade on Yemen and a recent attack on the international airport in Yemen's rebel-held capital, Sanaa. The Houthis said on Thursday they had attacked two Saudi oil tankers in the Red Sea, causing fires to break out on both.