Half of the ambulances targeted sustained serious damage and/or had to be withdrawn from service, the findings show.
Now in its eighth year, the Syrian conflict has taken a heavy toll on medical facilities and health professionals from airstrikes, bombings, shootings, kidnappings and lootings.
This is despite the fact that healthcare facilities and the ambulances servicing them are protected under International Humanitarian Law and the Geneva Conventions, and the UN resolution 2286, passed in 2016, condemning attacks on medical facilities and staff.
To try and quantify the extent of the damage inflicted on the country's ambulance service, the researchers analysed data from individual reports submitted to the Syrian Network for Human Rights (SNHR) throughout 2016 and 2017 and reviewed published research on attacks on ambulances since the start of the war in 2011.
Analysis of the SNHR data showed that there were 204 individual attacks involving 243 ambulances in 2016 and 2017. Half (52%) of the vehicles were deliberately targeted.
Most attacks occurred in areas with large factions of opposition forces: Aleppo, Idlib, and Damascus. Only 1-2 per cent of the attacks occurred in pro-government areas.
Half of the vehicles (49%) were either heavily damaged or had to be withdrawn from service. Only 12 per cent of vehicles sustained mild damage.
The principal perpetrators were the Syrian regime (123 incidents; 60%) and Russian armed forces (60; 29%). Air-to-surface missiles and shelling were most often used in the attacks.
Cluster bombs, which scatter munitions over a wide area, leaving unexploded remnants in the ground, and barrel bombs-unguided drums filled with metal fragments and explosives with a massive blast radius-are frequently used by Syrian government and Russian armed forces, note the researchers.
The high degree of indiscriminate and widespread destruction caused by these bombs will most likely have contributed to the large number of ambulances becoming collateral damage during attacks on medical facilities, they suggest.
The use of cluster bombs was banned in 2008 by the Convention on Cluster Munitions, indicating an "intentional disregard for international treaties on medical neutrality by the [Syrian] government," they point out.
The review of the published research (18 articles) included the impact of the attacks-care delayed or prevented altogether; blocking and other forms of violence, such as looting; the withdrawal of humanitarian agencies to protect workers; and 'double-tap' attacks, where a location is bombed twice, several minutes apart, with the intention of targeting first responders, including paramedics.
"This 'weaponisation of healthcare' turns the essential need for healthcare into a war tactic that aims to destabilise, intimidate, and demoralise," write the researchers.
"The intentional, highly destructive and repetitive targeting of ambulances throughout the Syrian conflict has had an immeasurable and devastating impact on the people of Syria and the healthcare system.
"As the most dangerous place in the world to be a healthcare provider, no cadre of health worker or health facility is immune to the attacks," they add.
Collecting data on attacks on ambulances and pre-hospital providers is challenging, but is nevertheless essential for ensuring that these incidents don't become "usual war-time tactics," insist the researchers.
"The UN Security Council and global humanitarian community must do more to protect the sacred space of medical neutrality in conflict and bring harsher punishments to perpetrators of violence against healthcare in Syria," they conclude.
BMJ Global Health