A major exchange of prisoners from Yemen’s brutal civil war got underway on Friday with the first plane departing rebel-held Sanaa for government-controlled Aden, the International Committee of the Red Cross said.

“The first flight from Sanaa has left,” ICRC media adviser Jessica Moussan told AFP, signalling the start of a three-day operation that will see nearly 900 prisoners released.

More than 300 prisoners will fly between the two cities on Friday. Later, detainees will also be released in Marib and Mokha, and in Riyadh and Abha in neighbouring Saudi Arabia.

The exchange is further evidence of a decrease in tensions after truce talks were held in Sanaa this week between the Huthi rebels and a delegation from Saudi Arabia, the government’s main military ally.

The Iran-backed Huthis seized control of Sanaa in 2014, ousting the internationally recognised government and triggering a Saudi-led military intervention the following March.

Hundreds of thousands of people have been killed by direct and indirect causes in a war that has sparked one of the world’s worst humanitarian crises, according to United Nations estimates.

Last month, Saudi Arabia and Iran agreed to re-establish official ties after a seven-year split, an announcement that has quickly redrawn the diplomatic map.

As part of the drawing down of tensions, nine Arab countries will meet in Jeddah, Saudi Arabia later on Friday to discuss the 12-year suspension from the Arab League of Iran ally Syria over its bloody civil war.