The Saudi-led coalition fighting in Yemen has said it will release 200 Houthi rebel prisoners and allow some flights out of the rebel-held capital, Sana’a – moves seen as a sign that efforts to end the five-year conflict are gaining momentum.

It said flights for Yemeni civilians needing medical care abroad would be overseen by the World Health Organization.

The news was greeted with rare approval from a senior member of the Houthi movement, Mohammed al-Houthi, while the International Committee of the Red Cross said it was ready to facilitate the freed prisoners’ repatriation.

The coalition did not give a timeframe for either of the developments, but Riyadh appears keen to capitalise on diplomatic progress made in the past month both with the Houthis and in healing a recent rift between the Yemeni government and southern separatists.

Hisham al-Omeisy, a political analyst and human rights activist, said: “There is still a lot of mistrust on all sides but unlike previous rounds of talks there’s a real incentive for Saudi Arabia to throw its weight behind negotiations this time. They’re serious about it.”

The Saudi-led coalition of Arab nations intervened in Yemen’s civil war against the Iran-backed Houthis in March 2015 after the rebels forced the government to flee to neighbouring Saudi Arabia.

The conflict has led to the world’s worst humanitarian crisis, with more than 100,000 people dead and 80% of the population dependent on aid to survive.

Saudi Arabia, the United Arab Emirates and western states selling weapons to the coalition have faced growing criticism over their roles in the stalemated war.

Riyadh has become increasingly isolated in recent months. The UAE announced in July that its troops would withdraw from Yemen and in September a drone attack on an Aramco oil facility sparked fears that the proxy conflict could escalate on Saudi soil. The attack, blamed on Iran, and muted reaction from Riyadh’s US allies showed new Saudi vulnerability.

Using Omani mediators, Saudi Arabia opened a direct channel with the Houthis for the first time in late September. The initiatives coincided with a unilateral release of 350 prisoners and offers of a ceasefire from the Houthis. The ceasefire has largely held up despite new fighting in the strategically important port city of Hodeidah this week.

This month Riyadh facilitated a breakthrough power-sharing agreement between the Yemeni government and the Southern Transitional Council (STC), a movement seeking renewed independence for Yemen’s south, after fierce fighting between the two former allies this summer.

In August the STC took control of Aden, which has served as the exiled government’s interim capital for years, effectively opening a new front in the complex war and threatening the stability of the wider coalition against the Houthis.

Meaningful progress with the Houthis is likely to prove much harder, however. Despite Saudi-led blockades and unremitting airstrikes, the rebels are unwilling to withdraw from the urban centres under their control, including Hodeidah and Sana’a.