(Read live updates from the ground here.This post has been updated.)

In the most serious outbreak of violence in months in Yemen, pro-regime forces cracked down on protesters over the weekend, killing at least 20 people Sunday and at least 20 more on Monday.

Among the dead were several children and soldiers who had defected to join the protesters, the Associated Press reports. Many of the protesters were killed by sniper fire.

Clashes began after thousands of protesters wielding sticks attempted to take over a camp belonging to the Presidential Guards in the capital Sanaa.

Frustration had built in recent weeks over President Ali Abdullah Saleh’s continued refusal to step down after 33 years in power.

Images of the injured or dead showed that many were left with severed limbs or maimed faces. Extremely graphic video has also emerged, including a video posted by activist group Media Center Sanna that showed a dead body of a young boy in a hospital bed, and another that showed a pile of dead bodies

Watch another video showing the protests today from the Media Center below:

Below, follow our live stream from journalists and others on the ground, many who used the hashtag #supportyemen.

Freelance journalist Tom Finn tweeted Monday: “Can barely describe what I'm seeing. Dead people everywhere. Even children.”