Yemen's Houthi movement, formally known as Ansar Allah and backed by Iran, expanded its control over key points along the Red Sea on Friday after a rapid military advance, seizing coastal areas of Yemen and islands inside the Bab el-Mandeb strait.
The gains strengthen the group's grip on one of the world's most important shipping passages, through which trade routes linking Asia and Europe pass. Tehran hailed the development. Houthi fighters, who until now controlled most of northern Yemen including the capital Sanaa and the western city of Hodeidah, pushed south within a matter of days.
An officer in the internationally recognised Yemeni government's army, which is backed by Riyadh, told Agence France-Presse that everything his forces had controlled on the west coast had fallen.
Saudi Arabia under pressure
Saudi Arabia, the world's largest crude exporter, now finds itself squeezed from two directions. On the other side of the Arabian peninsula, the Strait of Hormuz remains de facto blocked by Iran since war broke out in the Middle East.
Saudi infrastructure was also targeted this week in a large-scale attack involving drones and missiles launched by Ansar Allah. The kingdom was further forced to shut down its East-West pipeline, which it had used to bypass Hormuz, after the pipeline was struck by a drone attack that Riyadh said came from Iraq. Saudi authorities had already accused Iraqi armed groups aligned with Iran of trying to hit Saudi territory.
Oil prices pushed past the symbolic threshold of $100 a barrel, a sign of the renewed alarm sweeping markets after more than six months of war in the region that has already shaken the global economy. Brent crude, the international benchmark, was trading at around $104 a barrel on Thursday.
Despite the advance, the Houthis sought to reassure the international community. Yahya Saree, the military spokesman for Ansar Allah, said shipping remained safe for all companies, with the sole exception of Saudi vessels, which had already been barred from passage.
A 'brilliant' victory
Tankers and other commercial vessels use the Bab el-Mandeb strait to move between the Red Sea, the Suez Canal and the Mediterranean on one side, and the Indian Ocean on the other. Should the strait be blocked, the only alternative is the far longer and costlier route around Africa via the Cape of Good Hope.
Ansar Allah, which launched its offensive last week, captured the city of Mokha on Thursday, home to a strategically significant port, along with the island of Zuqar. It went on to take Mayun, also known as Perim, at the heart of the strait, as well as the last two islands in the maritime corridor, Greater and Lesser Hanish, according to sources close to the internationally recognised government.
In an effort to retake lost ground, the Saudi air force carried out bombing raids on the airport in Mokha, according to Al Masirah, a television network aligned with the Houthis. Forces loyal to the internationally recognised government said they had carried out raids of their own and urged civilians to avoid certain roads.
As the foreign ministers of Iran and Saudi Arabia held talks on Thursday over the situation in the region, an adviser to Iran's supreme leader, Ali Khamenei, described the Houthis' latest military success as a brilliant victory. Abdulhamid Daifallah, a Houthi supporter living in Sanaa, also praised what he called great victories, saying the islands in the Red Sea had been liberated within 72 hours. He added that Ansar Allah had been preparing for this front for four years.
Yemen 'on the edge'
After years of relative calm, Yemen began sliding back into war in July, against the backdrop of the wider Middle East conflict that erupted after an American-Israeli attack on Iran on February 28. Immediately afterwards, the Houthis announced a naval blockade of Saudi Arabia, targeting the kingdom's oil tankers.
Fighting in Yemen since last week has killed hundreds of people on both sides, most of them combatants, and forcibly displaced at least 46,000 people, according to the International Organization for Migration.
Farea al-Muslimi, a researcher at the British think tank Chatham House, said he believed the Saudis had tried everything to avoid this war, but that he did not think they still had a choice at this stage.
According to a report by the American news site Axios, which cited sources in Donald Trump's administration, the US president refused to order bombing raids against the Houthis despite a request from Riyadh to do so.
The situation in Yemen was the focus of an emergency meeting of the UN Security Council on Thursday. Hans Grundberg, the UN special envoy for Yemen, urged active engagement from the Security Council to step back from the edge of what he called a far more dangerous conflict.
