"When we first heard one explosion we ran to the basement. And then suddenly, boom, boom, boom - countless explosions. I will never forget that sound."
With a broken hand and shrapnel still lodged in her chest, Sveta, 55, had just survived a multiple rocket attack on her village when I met her in a hospital in Donetsk in eastern Ukraine this week. The attack destroyed her house and forced most of the villagers to leave. Our investigation shows that Ukrainian armed forces are responsible for at least some of the attacks here that have killed civilians.
Fighting in eastern Ukraine is intensifying between insurgent forces who took control over several towns and cities in April, and Ukrainian armed forces who are trying to drive them out. Government forces recently retook several towns, forcing the separatists to consolidate in a couple of cities, including Donetsk, the regional capital that usually is home to almost a million people.
The fighting is taking an increasing toll on civilians. Both sides talk about hundreds of civilian casualties. While the numbers are hard to verify, it is clear that civilian casualty figures are significant. One reason why so many civilians are getting injured and killed is the use of unguided rockets in populated areas, like the rockets that hit Sveta's village.
On July 12, for example, multiple rockets hit a residential area in the western part of Donetsk, killing seven civilians. One rocket killed four people from the same family, including two children, when it struck their home. In another attack the same day, multiple rockets hit another residential area just outside of Donetsk, killing six civilians. A more recent attack near the train station in Donetsk killed four civilians. The rockets that hit these areas were so-called Grads. These three-metre-long rockets can strike targets up to 20km away, but they are incredibly imprecise. At their maximum range, they are accurate within a rectangle of 336 metres by 160 metres, which means that if you are trying to hit a building, you would be lucky to hit somewhere on the same block.
But the most terrifying aspect of Grads is that they are often fired in salvos. A Grad rocket launcher, a truck with a grid of tubes on its trailer, is capable of launching 40 rockets within seconds. Often, several trucks fire their rockets at an area simultaneously, raining down dozens of rockets. Grad, the Russian word for hail, is a fitting, though euphemistic, nickname: The rockets literally rain down.
In these circumstances it can be challenging to establish who was responsible for a particular attack that killed civilians, particularly since both sides deny responsibility. But, in four attacks against populated areas that Human Rights Watch investigated in Donetsk, the evidence strongly indicates that Ukrainian government forces were responsible.
All the hits were in areas controlled by insurgent forces, but close to the front lines. And by examining the impact craters we were able to establish the rockets' flight direction, which indicated they had been launched from government-controlled areas. These four attacks killed at least 16 civilians and injured many more.
Insurgent forces also bear responsibility. Although Human Rights Watch has not yet conducted detailed investigations of insurgent-launched Grad attacks, there are persistent reports that they have been used in populated areas. In addition, insurgent forces and their weapons are deployed in populated areas in many places, endangering the civilians living there.
Because they are imprecise and cannot be relied upon to accurately target legitimate military objectives, the use of Grads in populated areas is a violation of the laws of war, and repeated attacks like those we documented could amount to war crimes. Commanders on both sides should recognise that they might one day be held legally accountable for their actions.
The Ukrainian government is ratcheting up its rhetoric, saying that it plans to retake all areas under insurgent control within weeks. That could spell disaster for civilians in eastern Ukraine unless both government and insurgent forces make commitments not to use Grad rockets in populated areas and to take other precautions to minimise civilian harm.
Ukraine's supporters in Washington, Brussels, and elsewhere in Europe, should make very clear they expect government forces to halt the use of Grad rockets and to strictly adhere to international humanitarian law. Russia denies it is supporting the insurgents, but Moscow obviously is influential among them, so it should use that influence to get insurgents to stop endangering the lives of civilians.