Israeli bombardment of Yemen capital Sanaa on Sunday killed at least six people and injured 86 others while causing huge fires in major oil facilities, making it one of the worst direct Israeli attacks on Yemeni targets in over a year.

More than 20 of the injured are in critical condition, according to a Health Ministry official from Yemen. The trading of missiles and bombings between Israel and Houthis is part of a spillover from the crisis in Gaza. Since Israel's offensive in Gaza began in October 2023, the Houthis have attacked Israeli targets and Isreal-related vessels in the Red Sea in solidarity with the Palestinians.

In a following statement, the Houthis vowed to retaliate, saying they would "not deviate from the fight" against Israel and its ally the United States "until the aggression stops and the (Israeli) blockade on Gaza is lifted", the Houthi-run Saba news agency reported.

The strikes targeted fuel and power stations, the presidential palace complex and other civilian facilities, although Israel claims they are military targets. The local Al-Masirah TV reported that a strike hit an oil facility owned by the country's main oil company and video on social media showed a fireball erupting at the plant.

Israel's military said 14 fighter jets struck the Asar oil facility and the Hizaz power plant, which it called "a significant electricity supply facility for military activities". The furthest target was nearly 2,000 kilometers from Israel.

But Abed al-Thawr, an official in the Houthi defense department, said Israel's claims that it attacked military targets on Sunday were "lies". He told Al Jazeera that Israel bombed civilian infrastructure to make Yemenis suffer, adding that the presidential palace hit on Sunday has long been deserted.

On Friday, the Houthis said they had fired a ballistic missile toward Israel's largest airport, Ben Gurion, in their latest attack. An Israeli Air Force official said on Sunday the missile most likely carried several sub-munitions "intended to be detonated upon impact".

Media outlets the Times of Israel and Ynet, citing the Israeli military, reported the missile had carried a cluster warhead, the first of its kind known to have been fired from Yemen.

The Israeli Defense Ministry released a photo on Sunday showing Prime Minister Benjamin Netanyahu, Defense Minister Israel Katz and military chief Eyal Zamir following the strikes against Yemen from a command bunker.

The escalation underscores the increasing entanglement of Yemen in broader regional tensions. By striking infrastructure in Sanaa, Israel aims to deter further missile and drone launches. Yet the Houthis retain significant capacity to disrupt maritime routes in the Red Sea, a vital artery for global trade, experts said.

The latest developments cast uncertainty over the fragile deescalation deal, said Yemeni political analyst Muqbel Naji.

"Any continuation of these exchanges will place the Red Sea at the heart of a multi-front crisis," he said, warning that international commercial lanes could face "greater exposure to disruption" if escalation continues.

He said the Houthis appear to have been reinforcing their positions and demonstrating their ability to sustain operations. "Israel's strikes may slow Houthi operations but are unlikely to dismantle the group's military capabilities," he said.

In May, the US announced a deal with the Houthis to end the airstrikes in return for an end to attacks on shipping, although the Houthis said the agreement did not include halting attacks on targets it believed were aligned with Israel.

Agencies and Xinhua contributed to this story.