An American soldier, a British soldier and one US contractor were killed Wednesday, a US official said, in the deadliest rocket attack in years on an Iraqi military base hosting foreign troops. The attack threatens a dangerous escalation, with suspected US-led coalition air strikes promptly targeting Iran-aligned Iraqi fighters in neighbouring Syria, a war monitor said. On Wednesday evening, a volley of rockets hit the Taji air base north of Baghdad, which hosts troops from the US-led coalition helping local forces battle jihadists. A coalition official first told AFP the force had sustained “several” injuries on Wednesday ranging from “light to critical,” but a US military official later confirmed three deaths. The Iraqi military said the rockets were fired from the back of a truck, but it did not comment on any casualties. There was no initial comment from Washington or London on those killed, nor was there an immediate claim of responsibility.Washington has blamed Iran-backed factions from Iraq’s Hashed al-Shaabi military network, which is incorporated into the Iraqi state, for similar violence in the recent past.Within hours of Wednesday’s attack, three warplanes likely belonging to the US-led coalition bombed Hashed factions stationed on the Syrian side of the border with Iraq, according to the Syrian Observatory for Human Rights war monitor.“Ten explosions shook the area near Albukamal,” said Observatory head Rami Abdel Rahman, citing a Syrian border town with a heavy Hashed presence.Hardline Hashed factions have fought alongside Syrian government forces for several years and have been targeted by both coalition and Israeli air strikes in Syria.