Qatar's Emir Sheikh Tamim bin Hamad Al-Thani arrived in Tehran Sunday, Iranian media reported, amid soaring tensions following the US killing of an Iranian commander and retaliatory strikes.
Qatar is close to the US and hosts Washington's largest military base in the region, but it also enjoys strong ties with Tehran, with which it shares the world's largest gas field.
Sheikh Tamim arrived in the Iranian capital around midday, semi-official news agency ISNA said.
The emir was scheduled to meet with President Hassan Rouhani in the afternoon, ISNA reported.
Qatar's Foreign Minister Mohammed bin Abdulrahman Al-Thani reportedly called for a peaceful solution that would lead to de-escalation during a visit to Tehran in the immediate aftermath of the US strike on January 3.
"Yes it's confirmed," an official at Qatar's Government Communications Office said, adding that Sheikh Tamim was flying to Iran for what is believed to be his first official visit to the Islamic republic, following a stop in Oman.
Sheikh Tamim left Doha for Muscat on Sunday morning "to offer condolences on the death of Sultan Qaboos", the state-run Qatar News Agency reported.
His visit follows the US killing of Iranian general Qasem Soleimani in a US drone strike near Baghdad's airport, and Iran's admission it accidentally shot down an airliner near Tehran on Wednesday, killing all 176 people aboard.
Iran retaliated against the US for Soleimani's death by firing missiles at American troops in Iraq, which US President Donald Trump said caused no casualties.
Qatar's relationship with Shiite-dominated Iran, seen as the major regional rival to Sunni-ruled Saudi Arabia, is one of the major factors underpinning a crisis between Qatar and its former allies.
Saudi Arabia, Bahrain, the United Arab Emirates and Egypt all cut ties with Qatar in 2017, accusing Doha of backing extremism and being too close to Iran, charges Qatar denies.