DUBAI, United Arab Emirates (AP) — Bahrain’s military said a third soldier died of his wounds on Wednesday after an attack by Yemeni rebels on a Bahraini contingent patrolling Saudi Arabia’s southern border.

The attack on Monday, which also wounded a number of soldiers, threatened recent progress in winding down Saudi Arabia’s eight-year war against the Iran-aligned rebels, known as Houthis. The rebels have not commented on the attack.

Bahrain says the rebels launched an unprovoked drone attack on the soldiers. Bahrain and its close ally Saudi Arabia condemned the attack, and the Saudi-led military coalition said it had “the right to respond at the appropriate time and place.”

It was unclear what impact the attack would have on the ongoing peace efforts.

Yemen’s war began in 2014 when the Houthis swept down from their northern stronghold and seized the capital, Sanaa, along with much of the country’s north. A Saudi-led coalition intervened in 2015 to try to restore the internationally recognized government to power.

The fighting soon devolved into a stalemated proxy war between Saudi Arabia and Iran, causing widespread hunger and misery in Yemen, which even before the conflict had been the Arab world’s poorest country. The war has killed more than 150,000 people, including fighters and civilians, and created one of the world’s worst humanitarian disasters, killing tens of thousands more.

Saudi Arabia and Iran restored diplomatic relations earlier this year in a deal brokered by China. Earlier this month, Saudi Arabia welcomed a Houthi delegation for peace talks, saying the negotiations had “positive results.”

A U.N.-brokered cease-fire largely halted the violence, and Yemen has seen only sporadic clashes since the truce expired nearly a year ago.

Bahrain’s military announced the third death on its social media sites.