The war in Syria killed 103 civilians in March, marking the lowest monthly non-combatant death toll since the start of the conflict in 2011, the Syrian Observatory for Human Rights said Wednesday (April 1st).

Of the total deaths, some 51 people were killed in shelling and airstrikes by the Syrian regime, the Observatory said.

The bulk of the remaining casualties were caused either by explosive remnants or mysterious "assassinations", it added.

The civilian death toll was more than double that number in February, when a regime offensive on Syria's north-western Idlib region was still in full swing and the monthly toll stood at 275.

The war in Syria has left more than 380,000 people dead since it started nine years ago, with the highest monthly toll recorded at 1,590 in July 2016, during battles between the Syrian regime and opposition forces in Aleppo.

The Syrian regime in early March paused a military offensive in the country's north-west, after a ceasefire brokered by regime ally Russia came into effect.

The Russia-backed campaign had displaced nearly a million people in the region since December, piling pressure on informal settlements already brimming with families forced to flee previous bouts of violence.

Concerns about displaced population

The fate of the displaced has been a key concern of aid groups amid an outbreak of novel coronavirus (COVID-19), which has killed two and infected eight others.

The UN has appealed for a nation-wide ceasefire to tackle the coronavirus threat, while aid groups have warned of a health catastrophe if the pandemic hits overcrowded displacement camps or crammed regime prisons.

The virus could spread faster in overcrowded refugee and displacement camps than it has anywhere else so far, the International Rescue Committee (IRC) warned Wednesday.

The IRC said its analysis showed transmission rates in some of the worst camps could outpace that witnessed during the dramatic quarantine of the Diamond Princess cruise ship off the coast of Japan.

"Refugees and displaced people in camps in Syria, Greece and Bangladesh face a heightened risk of COVID-19 due to living conditions that are even more cramped and densely populated than the Diamond Princess," IRC said.

"The rapid spread of COVID-19 on the Diamond Princess showed how the virus thrives in confined spaces but for millions of displaced people their conditions are far more cramped and poorly serviced and the risks are far deadlier," IRC's Marcus Skinner said.

According to the IRC, al-Hol displacement camp in Syria's al-Hasakeh province has a population density higher than that of the Diamond Princess, with 37,570 people per square kilometre.

Skinner said provided adequate funding came forward, some measures could be taken to mitigate the risk in camps, such as increasing access to running water, identifying isolation areas and building new shelters to support social distancing.