Abdul-Qader el-Murtaza, a Houthi official in charge of prisoner exchange talks in Yemen’s conflict, said 13 Houthi prisoners arrived Saturday in the capital, Sanaa.

He said the prisoners were released in exchange for a Saudi prisoner the Houthis freed. He did not say when the rebels released the Saudi prisoner.

Saturday’s release was part of a U.N.-brokered deal which Yemen’s warring parties stuck last month and includes the release of nearly 900 prisoners from both sides, el-Murtaza said.

The U.N.-brokered deal is scheduled to be implemented this month.

Yemen’s conflict began in 2014, when the Houthis seized Sanaa and much of the country’s north, ousting the internationally recognized government that fled to the south then into exile in Saudi Arabia.

The Houthi move prompted a Saudi-led coalition to intervene months later in a bid to restore the internationally recognized government to power. The conflict has in recent years turned into a regional proxy war between Saudi Arabia and Iran.

Omani officials, meanwhile, landed in Sanaa for talks with Houthi officials in the latest efforts to renew a ceasefire deal that expired in October, said Mohammed Abdul-Salam, the chief negotiator of the Houthi rebels.

Oman has for years hosted talks between the Iranian-backed Houthis and Saudi Arabia. The talks have been intensified since the warring sides failed to renew a U.N.-brokered cease-fire in October.

The negotiations in Oman's capital, Muscat focused on preventing all-out fighting after the ceasefire collapsed, and laying out a path for a negotiated end to Yemen’s civil war.

These talks have gained momentum in recent weeks after Saudi Arabia reached an agreement with Iran to restore their diplomatic ties after a seven-year rift. The Iran-Saudi deal, announced in Beijing on March 10, has invigorated hopes of a settlement to Yemen’s conflict.