China’s top diplomat has said that a Chinese-mediated detente between Iran and Saudi Arabia was driving a “wave of reconciliation” in the Middle East and pledged to firmly support Tehran on “issues concerning core interests”.

Wang Yi, the Chinese foreign minister, made the comments during a phone call with his Iranian counterpart Hossein Amir-Abdollahian on Sunday, according to China’s Xinhua news agency.

Wang told Amir-Abdollahian that Beijing appreciated Iran’s recent steps to improve ties with Saudi Arabia, including his meeting with Saudi Arabia’s Crown Prince Mohammed bin Salman in Jeddah.

Wang also pledged to “continue to support countries in the Middle East in exploring a development path that suits their own national conditions, strengthening communication and dialogue, adhering to unity and self-improvement, and realising good-neighbourliness and friendship”, Xinhua said.

The surprise detente between Iran and Saudi Arabia, brokered by China in March, followed years of bitter rivalry that had destabilised several Middle Eastern countries, including Iraq, Syria, Lebanon, Yemen and Bahrain.

Officials in Tehran and Riyadh have said the two countries’ deteriorating relations with the United States was one of the main reasons for their shift in policy.

Iran’s Supreme Leader Ayatollah Ali Khamenei wanted to end the political and economic isolation pushed by the US after it withdrew from a landmark deal curbing Tehran’s nuclear programme, and saw new relations with Saudi Arabia as a way to do so, Iranian officials have said.

Saudi Arabia had, meanwhile, lost confidence in any US commitment to shared regional security concerns and wanted to bolster ties with China, which has retained good relations with Iran.

Since the detente, the two countries have moved towards reopening diplomatic missions in each others countries and Prince Mohammed has accepted an invitation from Amir-Abdollahian to visit Tehran, according to Iran’s semi-official Tasnim news agency.

Iran’s foreign minister, during his call with Wang on Sunday, “expressed sincere gratitude to China for the constructive role it played in promoting the normalisation of relations between Iran and Saudi Arabia”.

He also briefed Wang on the latest progress on Iran’s talks with the US on the nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA).

For his part, Wang called for “the full and effective implementation of the JCPOA” to resolve the nuclear issue, Xinhua said.

The Iran-US talks, mediated by the European Union, began in Vienna two years ago but remain deadlocked with no public sign of progress.

However, earlier this month, Iran moved five Americans imprisoned in the country into house arrest and, according to media reports, may eventually release them as part of a deal under which $6bn in Iranian funds in South Korea would be unfrozen.

US Secretary of State Antony Blinken has said the nuclear talks and the potential release of detainees were “an entirely separate matter”.