The US on Tuesday denied that it had carried out dawn air strikes in Syria after Syrian and Iranian state media said US forces had bombed an eastern region and killed at least seven soldiers, including a member of Iran's Revolutionary Guards.
Syrian state media said a civilian was also killed and at least 19 other soldiers and 13 civilians were wounded in strikes on residential areas and military sites in Deir Ezzor province, with significant damage to public and private properties.
Iranian state media said a Revolutionary Guards adviser was killed in the air strikes, without giving his rank.
"We did not carry out air strikes in Syria last night," Pentagon spokesperson Sabrina Singh told reporters in Washington.
Iranian-backed forces in eastern Syria have previously attacked some of the 900 US troops based in the remote region. The United States has occasionally responded by carrying out strikes there against targets linked to Iran. Israel has repeatedly bombed Iranian targets in Syria.
Iran says its officers serve in an advisory role in Syria at the invitation of Damascus to support President Bashar al-Assad against internal and external foes including during a decade-long civil war with opposition forces who failed to topple him.
Two regional intelligence sources said Israeli jets conducted several strikes on two locations within Deir Ezzor city and Al Bukamal where Iran's Revolutionary Guards have outposts.
Iranian militias have a strong presence in Syria's eastern province of Deir Ezzor near the Iraqi border where Tehran has expanded its military presence, Western intelligence sources say.
The sources said another strike hit the town of Mayadeen along the Euphrates River which has become a major base for several Shiite militias, mostly from Iraq.
Israel, alarmed by Iran's growing regional influence and military presence in Syria, says it has carried out hundreds of strikes in Syria to slow down Iranian entrenchment. It has not commented on Tuesday's strikes.
Over the past year, strikes by unmanned Israeli aircraft have concentrated on the border town of Albu Kamal, southeast of Mayadeen, that lies on a strategic supply route for Iranian-backed militias who regularly send reinforcements from Iraq into Syria. The Iranian-backed militias are also in control of large stretches of the frontier on the Iraqi side.
Syria's Foreign Ministry condemned Tuesday's air strikes and said Washington was exchanging roles with Israel, adding that they sought to stir instability in the region.