A Saudi-led coalition fighting Iran-backed Houthi rebels in Yemen unleashed a barrage of air strikes on the capital and a strategic Red Sea city, officials said on Saturday.

At least eight people were killed.

The overnight air strikes on Sanaa and Hodeida — both held by the Houthis — came a day after the rebels attacked an oil depot in the Saudi city of Jiddah, their highest-profile assault yet on the kingdom.

Brig Gen Turki al-Malki, a spokesman for the Saudi-led coalition, said the strikes targeted “sources of threat” to Saudi Arabia, according to the state-run Saudi Press Agency.

Footage circulated online showed flames and plumes of smoke over Sanaa and Hodeida.

Associated Press journalists in the Yemeni capital heard loud explosions that rattled residential buildings there.

The Houthis said the coalition air strikes hit a power plant, a fuel supply station and the state-run social insurance office in the capital.

A Houthi media office claimed an air strike hit houses for guards of the social insurance office, killing at least eight people and wounding four others, including women and children.

The office shared images it said showed the aftermath of the air strike. It showed wreckage in the courtyard of a social insurance office with the shattered windows of a nearby multiple-storey building.

In Hodeida, the Houthi media office said the coalition hit oil facilities in violation of a 2018 ceasefire deal that ended months of fighting in Hodeida, which handles about 70% of Yemen’s commercial and humanitarian imports. The strikes also hit the nearby Port Salif, also on the Red Sea.

The coalition spokesperson was not immediately available for comment on the Houthi claims.

The escalation is likely to complicate efforts by the UN special envoy for Yemen, Hans Grundberg, to reach a humanitarian truce during the holy month of Ramadan in early April.

It comes as the Gulf Cooperation Council (GCC) plans to host the warring sides for talks late this month. The Houthis however have rejected Riyadh — the Saudi capital where the GCC is headquartered — as a venue for talks, which are expected to include an array of Yemeni factions.

Yemen’s brutal war erupted in 2014 after the Houthis seized Sanaa. Months later, Saudi Arabia and its allies launched a devastating air campaign to dislodge the Houthis and restore the internationally recognised government.

The conflict has in recent years become a regional proxy war that has killed more than 150,000 people, including over 14,500 civilians. It also created one of the worst humanitarian crises in the world.

The Houthis’ Friday attack came ahead of a Formula One race in the kingdom on Sunday, raising concerns about Saudi Arabia’s ability to defend itself against the Iranian-backed rebels.

Friday’s attack targeted the same fuel depot that the Houthis had attacked in recent days — the North Jiddah Bulk Plant that sits just south-east of the city’s international airport and is a crucial hub for Muslim pilgrims heading to Mecca.