Unidentified planes struck targets in Syria near the border with Iraq on Friday, reports said, triggering “a huge explosion” amid soaring tensions in the region between the United States and Iran. The Syrian Observatory for Human Rights said the planes targeted positions belonging to pro-Iran militias in the Al Bukamal area. The Britain-based organisation which monitors the war in Syria through a network of activists on the ground said the planes struck among other targets weapons depots and vehicles belonging to the militias. It reported several explosions in the border area. The Observatory head, Rami Abdel Rahman, said at least eight Iraqi militia fighters were killed. Deir Ezzor 24, an activist collective that reports on news in the border area, said the strikes targeted lorries carrying weapons and depots for ballistic missiles. Omar Abu Laila, a Europe-based activist from Deir Ezzor province who runs the group, said the attack triggered “a huge explosion”. The Sound and Picture organisation, another activist collective in the eastern Syrian province, also reported strikes along the Iraq border by “unidentified planes”. There was no immediate comment from Syria or Iraq, and the reports could not be independently confirmed. The US carried out military strikes in the area on December 29, killing 25 members of an Iran-backed Iraqi militia in retaliation to a rocket attack on a military base in Iraq that killed a US contractor. The US blamed that attack on Iraq's Kataib Hezbollah militia. Israel has also struck Iran-backed militias in the area in the past. The latest air strikes came days after a US drone strike killed Iran’s most powerful general, Qassem Suleimani, after he landed at Baghdad airport, drawing angry calls for revenge and escalating tensions to the brink of an all-out war between the two sides. The leader of Kataib Hezbollah, Abu Mahdi Al Muhandis, was also killed in the attack on January 3. Iran responded by firing a barrage of missiles at military bases in Iraq that host US troops. Since then, both sides signalled they were stepping back from further escalation but tensions remain high and the region on edge. Amid the soaring tensions, Russian President Vladimir Putin made a rare visit to Syria this week for talks with President Bashar Assad in Damascus. Russia has been a key ally for Mr Al Assad, offering crucial military and political backing throughout the country’s civil war. The area struck on Friday is key to a land corridor for Tehran that links Iran to the Mediterranean through Iraq, Syria and Lebanon.