Following the United States cruise missile strike on Syria last week and talk of a potential shift in American policy, White House spokesman Sean Spicer added to the confusion on Monday by suggesting that barrel bombs were another “red line” that would trigger military action. The White House later amended the statement to say he was referring to barrel bombs containing industrial chemicals like chlorine.

“The sight of people being gassed and blown away by barrel bombs ensures that if we see this kind of action again, we hold open the possibility of future action,” Spicer said at a daily press briefing.

According to the Syrian Observatory for Human Rights, the Syrian government dropped barrel bombs on rebel-held areas shortly after Spicer’s remarks. In March, Syrian President Bashar al-Assad’s military dropped 495 barrel bombs, killing 10 people, according to the Syrian Network for Human Rights. The organization counted nearly 13,000 barrel bombs dropped from helicopters last year, resulting in 653 civilian deaths.

Syria Deeply talked to Erin Hunt, program coordinator for Mines Action Canada, about the use of barrel bombs in Syria.

Syria Deeply: What are barrel bombs and how have they been used in the war in Syria?

Erin Hunt: Barrel bombs are essentially improvised explosive devices, so they’re barrels filled with explosive devices and they’re usually dropped from the sky. They are relatively unique to the Syrian conflict [in terms] of the civilian harm caused by using explosive weapons in populated areas. They’ve been used for a number of years and they come in all sorts of different shapes and sizes. There’s a huge difficulty in delivering them accurately to the target, which means that they often have a very wide effects, which can be especially problematic in a populated area. And what we see when explosive weapons of any type, including barrel bombs are used in populated areas, the majority of the victims are civilians.

And then there are longer term and indirect harms that will continue to affect the community for years afterwards. Anything that’s a large amount of explosive in a city or populated area is going to take out a lot of very important civilian infrastructure, especially if you can’t control where it lands. A lot of the times, because barrel bombs have become very emblematic of the conflict in Syria, we forget that these are improvised explosive weapons and the humanitarian impacts they have are similar to rockets or aircraft bombs. The strong international condemnation of barrel bombs attacks sort of reflects the general stigma that comes with bombing cities and towns.

Syria Deeply: How has the impact and usage of barrel bombs changed over the years?

Hunt: What we’ve seen throughout the conflict is the use of explosive weapons including barrel bombs becoming exceptionally heavy in populated areas, with cities seeing high level of bombardment especially in combination with siege tactics. We’re seeing indiscriminate bombing of civilian areas and the use of barrel bombs and other explosive weapons, which is contrary to international humanitarian law. Civilians are never an appropriate target, and civilian objects and infrastructure are never an appropriate target for any of these explosives. But we’ve seen that happening a lot, including the targeting of hospitals and schools. We need to focus on condemning that usage, whether it’s a barrel bombs or a traditional mortar. We just haven’t had as much of that from the international community as we would like.

Syria Deeply: The White House has now included barrel bombs carrying industrial chemicals under its red line. How have the types and capacities of these bombs changes?

Hunt: This has been going on for a number of years. The U.N. and other outside agencies have been looking at the use of chlorine and reported on them frequently. So it is curious that this is getting attention now. We do need to be looking at the fact that banned weapons have been used throughout this conflict in Syria, whether it’s landmines, whether it’s cluster munition, whether it’s chemical weapons as well as banned tactics like bombing hospitals, shelling cities. There are many things that should be condemned and we need to be focusing on all of it.

Sometimes it feels like it’s splitting hairs. We see that conventional weapons have caused the majority of deaths in Syria and especially amongst civilians. We need to prohibit the weapons and prohibit the tactics. We don’t say that strongly enough. There’s a focus on specific types of weapons but [the Assad regime finds] many other ways to cause civilians immense suffering.

Syria Deeply: How much worse can it get?

Hunt: What we’ve seen with the siege and bombardment combination that a lot of cities have seen, specifically Aleppo and some parts of Idlib now, it’s hard to imagine that humanity could get worse to each other than that. But I know that the depth to which people can go is pretty deep. I think we need to start reiterating some of the basics. Bombings of civilians and cities and towns are unacceptable. These are things that have been illegal in international humanitarian law for decades. We need to be stronger in protecting on those norms and laws and in holding those who break them accountable.

Syria Deeply: The U.S. strike on a Syrian air base last week was considered “proportional” response to chemical attack. How do you carry out retaliation that would be considered “proportional” to a barrel bomb attack?

Hunt: I honestly don’t know the answer to that. Barrel bombs that are improvised explosive devices, mortars and any sort of explosive weapons with a wide area effect — we have to figure out how to respond to all of these attacks. I’m still trying to sort out what everyone means by the change in rhetoric over the last few days and what are the on the ground consequences for this and what’s next. As someone who works in humanitarian disarmament, my questions are: How are we going to help the people rebuild their lives after cities have been destroyed? How are we going to rebuild water systems, electrical grids, hospitals and schools? What’s always on the back of my mind is, how do we as the international community support the people of Syria to rebuild?

This interview has been edited for length and clarity.

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