The complaint comes in the midst of an escalating diplomatic spat between the two nations, which began with the start of the Gaza war in October 2023 and worsened after Madrid recognised a Palestinian state a year later.

Filed by Shurat HaDin, which has taken legal action worldwide against what it calls "Israel's enemies", the lawsuit accuses Spain of providing "components required by the regime in Tehran and its proxies for military purposes".

In a filing submitted under Article 15 of the Rome Statute, it alleges that Spain approved the export of about 1.3 million euros' worth of so-called dual-use products that could be used in detonators and other explosive-related applications.

"These materials are not innocent industrial products, but critical components that enable explosive devices to function, and they were transferred in circumstances where their use for attacks against civilians was foreseeable and reasonable," Shurat HaDin said in a statement.

On February 28, Israel and the United States began striking Iran, which hit back by firing ballistic missiles and drones at countries across the region, until a shaky ceasefire deal took hold last week.

Ties between Israel and Spain have nosedived since the Gaza war sparked by Hamas' October 2023 cross-border attacks, with Israel angered by Sanchez's unrelenting criticism of its bombardment of the Palestinian territory.

Spain's Socialist leader has also opposed the US-Israeli war with Iran, drawing a sharp Israeli reaction.

Last week, Israeli Prime Minister Benjamin Netanyahu barred Madrid from joining the work of a US-led centre to stabilise post-war Gaza, accusing Spain of waging a diplomatic campaign against Israel.

Both countries have withdrawn their ambassadors.