QAIM, Iraq — Cross-border artillery shelling still shakes the Anbar province border city of Qaim at night, as fighting continues against Islamic State (IS) pockets north of the Euphrates River in Syria.

When still-unidentified aircraft struck a base June 17 used by Shiite militias consisting mostly of Iraqi fighters in al-Heri, south of the Euphrates in Syrian regime-held territory, the dozens of dead and wounded fighters were taken across the border into Iraq to the sole functioning hospital in Qaim, still under rehabilitation.

The US-led anti-IS coalition has denied that it was involved, and as Al-Monitor reported, some say that the airstrike was likely conducted by Israel. No confirmation was forthcoming, however, and the incident was only the latest potential powder keg threatening a still-precarious peace in the crucial border area.

Asaad Khalaf, a doctor and director of the hospital to which the dead and injured were sent, confirmed to Al-Monitor that the fighters had been brought there for emergency treatment but had not been authorized to give any details on their nationalities or other information.