What to know about the return to fighting in Yemen

The war in Yemen between government forces and the Iran-backed Houthi rebels has reignited after several years of calm, with more than 300 killed in the latest burst of renewed fighting. Experts say the Houthis hope to take land along the Bab al-Mandab Strait, the vital entrance to the Red Sea through which much world trade passes and which has become a key conduit for Saudi oil bypassing the Iranian-blockaded Strait of Hormuz. Here are key facts about what is happening in Yemen. The importance of Bab al-Mandab Since Thursday, the fighting in Yemen has been concentrated in the southwest, close to Bab al-Mandab, which in peacetime allows access to the Suez Canal and the Mediterranean, significantly shortening journeys to Europe and North America from Asia. A successful Houthi offensive would strengthen the ability of the rebels to threaten shipping in the Red Sea and Gulf of Aden, which they attacked during much of the Gaza war, forcing many commercial ships into long detours around southern Africa. Iran's blockade of Hormuz, on the other side of the Arabian Peninsula, has added further significance to Bab al-Mandab, because Saudi Arabia has diverted most of its oil exports to the Red Sea. Between March and mid-July, Saudi exports via Bab al-Mandab increased eightfold. "Whoever controls Bab al-Mandab can dictate their terms," said Yemeni researcher Ahmed Hazaa. The role of Iran Though independent, the Houthis are backed and supplied by Iran. In June, Iranian media warned that Tehran and its allies would "activate other fronts including the Bab al-Mandab Strait". Analysts are divided though, over the extent to which outside forces are behind the new fighting. Hazaa said the Houthi offensive was "clearly aimed at helping Iran with its blockade of Hormuz". "The Yemenis gain nothing from this war. It's a regional war directed by other players." But Farea Al-Muslimi, of the London-based Chatham House think tank, was less convinced. "I don't think this is necessarily directed by the Iranians," he told AFP. He said that while Iran might benefit from Houthi operations against Riyadh, that didn't mean it was calling the shots. Houthi strengthening, government fractiousness Eight years of fighting, between 2014 and 2022, plunged Yemen into one of the world's worst humanitarian crises. The UN warned last year that 17 million people were struggling to eat and a further million faced extreme hunger in Yemen, one of the region's most populous countries. The war, which has pitted the Houthis against the internationally recognised government, has seen the rebels take over most of the country's major population centres, including the capital Sanaa. The government and its backers, meanwhile, have clung on to Aden in the south, as well as the key port of Mokha on the Bab al-Mandab strait. A short-term truce in 2022 froze the frontlines and ended up lasting until July, when fighting suddenly resumed. The fighting was sparked by the arrival in Sanaa of an Iranian plane without Saudi authorisation, in defiance of Riyadh's control over Yemeni airspace. There were strikes against Sanaa airport, blamed on the Saudis, followed by Houthi retaliation, with combat escalating in intensity and causing thousands of civilians to flee. Al-Muslimi said the current offensive was "not a surprise". The Houthis made use of the 2022 truce to train their forces, build up their arsenal and develop new technologies, he said. Faced with that, pro-government forces, a fractious and heterogeneous grouping of factions, have splintered further. "They simply aren't in the habit of coordinating among themselves," Al-Muslimi said.