Raisi arrived in Doha on the first visit by an Iranian president to Qatar in 11 years and as Gulf states closely watch indirect US-Iranian talks to salvage a 2015 nuclear pact.
"Iran is one of the founders of the Gas Exporting Countries Forum (GECF) because we are among the three most important gas producing and exporting countries," Raisi said before he left Tehran to attend the gas summit being held on Tuesday.
Raisi, on his third foreign trip since taking office, is due to meet with Qatar's emir, whose foreign minister has held talks in Washington and in Tehran in recent weeks on efforts to salvage the nuclear pact, which Washington had withdrawn from in 2018.
Saudi Arabia and its Gulf allies have urged global powers involved in the nuclear talks to also address Iran's missiles programme and network of regional proxies.
Qatar has good ties with Iran, with which it shares a giant gas field. Tehran supported Doha after Saudi Arabia and its Arab allies imposed a boycott on Qatar in mid-2017 in a dispute over its ties with Islamist groups and non-Arab Turkey and Iran.
The Gulf row was resolved early last year and Saudi Arabia, which is locked in several proxy conflicts with Iran, has been engaging directly with Tehran in a bid to contain tensions.
