A government crackdown in Yemen on Friday left more than 40 anti-government protesters dead and hundreds wounded in the Yemeni capital, Sana'a.

A demonstrator stands above the crowd, screaming and waving a graffitied national flag.

Until today, the protests had been largely peaceful, with only minor skirmishes between protesters and government forces. However, there has been an increasingly heavy presence of riot police.

In the photo below, two boys peek through a torn Yemeni flag on 17 March, the day before the crackdown.

Above: women pray in the nation's capital at a rally aimed at removing President Ali Abdullah Saleh, 17 March.

Below, a man raises his bloodstained hands to the camera after government forces attacked protesters, 18 March.

Protesters carry away a wounded boy to receive medical treatment.

Another injured protester is stretchered away by chanting demonstrators.

(All photos: Getty Images)