In a report last year by the Saudi Arabia-led, anti-Assad High Negotiations Committee, Syrian opposition groups claimed that North Korean forces had been spotted fighting on behalf of the Syrian government, according to the state-run Tass Russian news agency. The U.N. has also accused North Korea of helping Assad build chemical weapons, which the Syrian leader denies possessing.

Syria, Iran and North Korea are all leading critics of U.S. foreign policy and have been subject to widespread U.S. sanctions. Iran and North Korea, along with Iraq under President Saddam Hussein, were designated part of President George W. Bush's "Axis of Evil" in 2002. This was later that year expanded by then-Undersecretary of State John R. Bolton to include Syria, along with Fidel Castro's Cuba and Muammar el-Qaddafi's Libya.

In response to Bush's 2002 speech, Libyan official newspaper Al-Zahf Al-Akhdarbranded Iran, Iraq and North Korea as part of an "axis of resistance," a term used commonly today by opponents of U.S. foreign policy to describe Syria, Iran and Iran-backed Lebanese Shiite Muslim movement Hezbollah, which is considered a terrorist organization by the U.S and provides a vital column of support for Assad in Syria.