Iran's consulate in the Syrian capital Damascus was flattened on Monday in what Syrian and Iranian media described as an Israeli air strike.
A Lebanese security source, speaking to Reuters, said one of the dead was Mohammad Reza Zahedi, a senior commander in Iran's Revolutionary Guards Corps (IRGC). Iranian state television said several Iranian diplomats had been killed.
Israel, which has repeatedly hit Iranian targets during the six-month war in Gaza, declined to comment on the incident, following its usual practice.
An Israeli military spokesperson said: "We do not comment on reports in the foreign media."
Iran's Tasnim news agency said five people were killed in the Israeli strike. Syria's SANA state news agency reported an unspecified number of deaths and injuries.
Since the Palestinian group Hamas' attack on Israel on October 7, Israel has ramped up airstrikes in Syria against Lebanon's Hezbollah militia and Iran's Guards, both of which support the government of President Bashar Al Assad.
U.S. National Guard troops patrolling the streets of Washington D.C. as part of what President Donald Trump said was his crackdown on crime will begin carrying weapons on Sunday night, two officials said.
Israeli strikes hit the Yemeni capital Sanaa on Sunday in retaliation for Houthi missiles fired towards Israel, with a Houthi health official saying the attack killed six people and wounded 86.
Syria's first parliamentary election under its new Islamist administration, scheduled for September, will not include the southern province of Sweida and two other provinces due to security concerns, the electoral commission said on Saturday.
Ukraine launched a drone attack on Russia on Sunday, forcing a sharp fall in the capacity of a reactor at one of Russia's biggest nuclear power plants and sparking a huge blaze at the major Ust-Luga fuel export terminal, Russian officials said.
Ukrainian President Volodymyr Zelenskyy marked Independence Day on Sunday alongside Canadian Prime Minister Mark Carney, who said Ukraine would receive more than C$1 billion ($723 million) in military aid from a previously announced package next month.