A weeklong ceasefire appeared to be holding in Yemen on Tuesday as leaders of the country’s warring factions met in Geneva, Switzerland for peace talks.

Just before the truce was due to come into effect, two commanders from Saudi Arabia and the United Arab Emirates were killed when Houthi rebels struck an army camp near the city of Taiz on the Red Sea.

The Saudi-led coalition that claims to seek the restoration of President Abd Rabbuh Mansur al-Hadi, who was ousted in January, retaliated with airstrikes around Taiz and along the Saudi border with Yemen, the Houthis said.

Earlier negotiations in Geneva, held by the United Nations, failed to end the conflict.

The nominal purpose of Tuesday’s talks is to reach agreement on how to implement a UN Security Council resolution passed in April that calls on the Houthis to vacate several of the cities they have captured, including the capital, Sana’a.

Foreign involvement

Neighboring Sunni states, led by Saudi Arabia, intervened in March to halt what they saw as a Iranian-backed insurgency in Yemen.

But the Houthis, who adhere to an offshoot of Shia Islam, had been fighting Yemen’s government for years before the Shia state threw its support behind them.

The conflict came to a head when Hadi proposed constitutional reforms that would have split the country up into six autonomous regions. The Houthis teamed with supporters of Hadi’s predecessor, Ali Abdullah Saleh, to block a plan they argued would have eroded national unity.

The reforms were also resisted by separatists in the former South Yemen, if for the opposite reason. They have since formed the backbone of the anti-Houthi movement.

Hadi, still the internationally-recognized leader of Yemen, does not command a following of his own.

His foreign backers have had to rely on southerners and Yemen’s Muslim Brotherhood to help push back the Houthis on the ground.

Ironically, it was fear of a Muslim Brotherhood takeover in 2012 that compelled Saudi Arabia to facilitate Saleh’s ouster at the time.

Saleh, a northerner, presided over Yemen’s unification in 1990 and had ruled the country since.