At least five people were killed on Saturday in an explosion in central Saada, a town in northwest Yemen at the heart of a Shia revolt. According to a witness, the blast near Saada's post office left a number of people wounded. Rescue services evacuated the casualties as security forces sealed off the site. Yemen's Saada province in the mountains on the border with Saudi Arabia has been the heartland of an uprising launched by Zaidi Shia rebels in 2004 in which thousands of people have died. The two sides signed a Qatari-brokered peace deal in June last year but there has been repeated wrangling about its implementation. The insurgents are known as Huthis after their late commander, Hussein Badr Eddin al-Huthi, who was killed by the army in September 2004. He was succeeded as field commander by his brother Abdul Malak. Yemen, one of the poorest countries outside of Africa, is also grappling with a violent campaign by Al Qaeda militants, dwindling oil and water resources, and unemployment.