Who are the Houthi rebels and what are their links to Iran?

The UK and US have launched a second wave of missile strikes against Houthi military targets in Yemen amid escalating tension sparked by the movement's attacks on international shipping in the Red Sea late last year.

The Houthis are a part of what has been dubbed the "Axis of Resistance" - an anti-Israel and anti-Western alliance of regional militias (Hamas, Hezbollah and Houthis) which is backed by Iran.

The second set of strikes in Yemen, which were once again supported by Australia, Bahrain, Canada and the Netherlands, are a dramatic and significant widening of the Israel-Hamas war in Gaza.

“Our aim remains to de-escalate tensions and restore stability in the Red Sea, but let us reiterate our warning to Houthi leadership: we will not hesitate to defend lives and the free flow of commerce in one of the world’s most critical waterways in the face of continued threats,” a joint statement from the US and UK said.

Here, Yahoo News UK breaks down who the Houthis are, where they are based, and what their relevance is.

Who are the Houthi rebels?

The Houthis are described by the Counter Extremism Project (CEP), an organisation which works to combat extremist groups and ideologies, as "an Iranian-backed, Shiite Muslim armed religious and political movement in Yemen".

The Houthis are at the centre of Yemen's civil war. According to a US Department of State report, they control "one-third of the country’s territory, which contains 70% to 80% of the population".

The group swept into Yemen's capital, Sanaa, in 2014 when it ousted the internationally recognised government.

Saudi Arabia and the United Arab Emirates intervened in the war in 2015 to try to restore the government, but the conflict has dragged on - with dire consequences.

In 2021, the UN estimated the war had caused 377,000 deaths through direct and indirect causes such as poor food security and a collapse of public services. The agency also says more than 11 million children are in need of humanitarian assistance.

Meanwhile, the below image shows how hundreds of children have been killed by Houthi-laid landmines and explosive devices.

The Houthi movement is also known for its anti-American and anti-Semitic rhetoric. Its slogan reads: “God is great, death to America, death to Israel, damnation to the Jews, victory to Islam.”

How and why does Iran support them?

Iran and Saudi Arabia are engaged in proxy wars in several Middle Eastern countries. In Yemen, that manifests with Iran's backing of the Houthis and Saudi's backing of Yemen's official government.

The UK has previously handed evidence to UN Security Council members demonstrating how the Iranian regime sends weapons to the Houthis.

However, it is not entirely clear how deep that relationship goes. The Saudi-led coalition accuses Iran of arming and training the Houthis, a charge both deny. The coalition also says Lebanon's Iran-backed Hezbollah is helping the Houthis, an accusation it rejects.

Yemen experts say the Houthis are motivated more by a domestic agenda and the group itself says they are fighting a corrupt system and denies being puppets of Iran.

The Wilson Center, the US global affairs think tank, says: "Yemeni officials and Sunni states have repeatedly alleged that Iran and its proxy Hezbollah have provided arms, training, and financial support to the Houthis. But Iranian and Hezbollah officials have denied or downplayed the claims."

How do they link to the Israel-Gaza conflict?

The Houthi movement has a long-standing association with Hamas and their ties have fed Western fears that the most recent Gaza conflict could spread.

The CEP points out: "Higher-ups in the Houthi movement have expressed support for Hamas. Before he was killed in 2004, Houthis founder Hussein al-Houthi made it a point to praise Hamas for its wars against Israel."

It adds Hamas "maintains a representative in Houthi-held territory in Yemen".

On 10 October, three days after the Israel-Gaza conflict began, Houthi leader Abdel-Malek al-Houthi warned the group would respond to US involvement by firing drones and missiles.

He said "there are red lines when it comes to Gaza" and that the Houthis were ready to coordinate with other groups and intervene.

The US, which is Israel's closest ally, subsequently sent a significant amount of naval power to the Middle East, including two aircraft carriers, their support ships and about 2,000 Marines.

Houthi attacks on Israel

Last year, the US started intercepting several drones launched by the Houthis potentially towards targets in Israel.

This escalated further when the Houthis started launching attacks on shipping routes in the Red Sea in a show of support for the Palestinians and Hamas, the Islamist group that controls Gaza. In November, the group seized the Galaxy Leader, a Japanese-operated cargo ship linked to an Israeli company.

The Houthi attacks have disrupted international commerce, forcing international shipping to take the long route around South Africa to avoid being struck. The increase in delivery costs has stoked some fears it could trigger a fresh bout of global inflation.

On 4 January this year, members of the UN Security Council called on the Houthis to halt their attacks on shipping describing them as illegal and threatening regional stability, freedom of navigation and global food supplies.