(Bloomberg) -- A senior United Arab Emirates royal met with Iran’s President Ebrahim Raisi in Tehran on Monday, marking the highest-level visit in more than a decade as the UAE seeks to reduce tensions that have threatened in recent years to slide toward conflict. 

Sheikh Tahnoon bin Zayed, the UAE’s national security advisor, promised to seal improving ties by developing trade and investment. He gave no details and it wasn’t clear how that would tally with U.S. secondary sanctions on the Islamic Republic. 

A brother of Abu Dhabi’s crown prince, Sheikh Tahnoon has taken the lead in the UAE’s effort to step back from divisions that have defined the region for the past decade, with visits to Turkey and Qatar paving the way to a restoration of ties this year. 

Differences with Iran are more complicated due to the country’s nuclear program and its proxy militias in Iraq, Yemen and Lebanon, which Saudi Arabia and other Gulf Arab countries accuse of destabilizing the world’s largest oil-exporting region. 

Gulf Arab rivalry with Iran split the region and exacerbated conflicts for years, but the two regional powers have held several rounds of Iraqi-mediated talks this year, meeting even during the six months when nuclear talks between world powers and the Islamic Republic were stalled.

Saudi Arabia, which has battled Iranian-backed Houthi fighters in Yemen since 2015, is pushing to end a war that’s exposed its oil facilities to drone and missile attacks. Iran wants diplomatic missions to be opened first.

Iran Quietly Pushes to Reopen Saudi Missions as Talks Inch Ahead

The UAE has quietly worked to mend ties since a spate of attacks on shipping in the Gulf and a drone and missile strike on a major Saudi oil facility brought the region to the brink of conflict in 2019.  It has stepped up those efforts since the election of Joe Biden. The Biden administration has sought to re-engage with Iran and revive the 2015 nuclear deal which his predecessor abandoned. 

The visit aims to strengthen “communication and cooperation in the region,” the UAE diplomatic adviser to the presidency, Anwar Gargash, wrote on Twitter. 

Syria’s Foreign Minister Faysal Mikdad is also in Tehran to meet with Iranian counterpart Hossein Amirabdollahian. The UAE’s Foreign Minister Sheikh Abdullah Bin Zayed Al Nahyan visited Damascus last month and met with Syrian President Bashar al-Assad. He also discussed with Assad ways to boost joint investments in key sectors, the state-run Syrian news agency reported without giving details.

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