Israel is behind an attack on the Iraq-Syria border that left dozens of militia fighters dead, CNN reported yesterday, citing a US official.

An airstrike on Sunday night targeting pro-Assad forces fighting Daesh was initially blamed on the US by Syrian state media. The strike took place in Al-Hari military base, southeast of Albu Kamal, with the death toll reaching 52 according to the Syrian Observatory for Human Rights. The US military denied it was responsible.

According to CNN, the latest attack is unlike those normally carried out by Israel, which usually occur in the west of the country around Damascus and Homs. Sunday’s attack took place in the east, but also targeted Iraqi forces, as opposed to Iranian ones.

Yesterday, Iraq’s Foreign Ministry issued a statement expressing “rejection and condemnation of any air operations targeting forces in areas where they are fighting ISIS [Daesh], whether in Iraq or Syria or any other area where there is a battlefield against this enemy that threatens humanity.”

The latest attack comes less than a month after Israeli missiles struck some 50 separate sites in the south of Syria and around Damascus; Israeli Defence Minister Avigdor Lieberman later said the attack had destroyed almost all Iran’s entire military infrastructure in the country. The move came after Iran launched some 20 rockets towards the Golan Heights. Whilst most of the rockets landed in Syrian territory, Israel’s Iron Dome defence system destroyed four missiles that crossed into occupied territory.

“Iran is the one constantly trying to expand and create new proxies and fronts,” Lieberman told the annual Herzliya Conference. “We hit almost the entire Iranian infrastructure in Syria … They must understand that if it rains here, it will pour there.

Israel has repeatedly struck Syrian army locations in the course of the conflict, hitting convoys and bases of Iranian-backed militias that fight alongside Assad’s forces; on 9 April, an Israeli strike killed seven Iranian military personnel at a Syrian airbase, with Tehran vowing to retaliate.

Israel has accused Iran of seeking a permanent military presence in Syria, and expanding its influence via a belt of territory that stretches from the Iraqi border to the Lebanese border.