Syrian state news agency SANA initially reported the explosion, with local news source Deir Ezzor 24 reporting that the explosion was believed to have been caused by a mortar shell and that sirens were heard in the area.
Media close to al-Hashd al-Shaabi (Popular Mobilization Forces-PMF) said that the attack was waged by members of the Iraqi paramilitary group.
A US defense official later told Reuters that US forces in the Conoco gas fields in eastern Syria took indirect fire on Saturday but initial reports did not indicate any casualties or damage.
The incident is the latest attack on US forces in Iraq and Syria.
US diplomats and troops in Iraq and Syria were targeted in three rocket and drone attacks on Wednesday alone, including at least 14 rockets hitting an Iraqi air base hosting US forces, wounding two American service members.
As there haven't been immediate claims of responsibility for these attacks, analysts believe they were carried out by Iranian-backed militias.
Iraqi militia groups aligned with Iran had vowed to retaliate after US strikes on the Iraqi-Syrian border killed four of their members last month.
Iran has denied supporting attacks on US forces in Iraq and Syria, and condemned US air strikes on Iranian-backed groups.