Yemeni protesters push down a wall that was used by protesters for peaceful sit-in in the Change Square in Sanaa, Yemen, on April 19, 2013. Yemenis began to remove tent camps in the capital Sanaa and other cities in the country, declaring the end of their peaceful sit-in which was a part of revolution that forced former President Ali Abdullah Saleh to step down last year. (Xinhua/Mohammed Mohammed)

Yemeni protesters start to remove tent camps that were used by protesters for peaceful sit-in in the Change Square in Sanaa, Yemen, on April 19, 2013. Yemenis began to remove tent camps in the capital Sanaa and other cities in the country, declaring the end of their peaceful sit-in which was a part of revolution that forced former President Ali Abdullah Saleh to step down last year. (Xinhua/Mohammed Mohammed)

Yemeni protesters start to remove tent camps that were used by protesters for peaceful sit-in in the Change Square in Sanaa, Yemen, on April 19, 2013. Yemenis began to remove tent camps in the capital Sanaa and other cities in the country, declaring the end of their peaceful sit-in which was a part of revolution that forced former President Ali Abdullah Saleh to step down last year. (Xinhua/Mohammed Mohammed)

Yemeni protesters start to remove tent camps that were used by protesters for peaceful sit-in in the Change Square in Sanaa, Yemen, on April 19, 2013. Yemenis began to remove tent camps in the capital Sanaa and other cities in the country, declaring the end of their peaceful sit-in which was a part of revolution that forced former President Ali Abdullah Saleh to step down last year. (Xinhua/Mohammed Mohammed)

Yemeni protesters push down a wall that was used by protesters for peaceful sit-in in the Change Square in Sanaa, Yemen, on April 19, 2013. Yemenis began to remove tent camps in the capital Sanaa and other cities in the country, declaring the end of their peaceful sit-in which was a part of revolution that forced former President Ali Abdullah Saleh to step down last year. (Xinhua/Mohammed Mohammed)

Yemeni protesters start to remove tent camps that were used by protesters for peaceful sit-in in the Change Square in Sanaa, Yemen, on April 19, 2013. Yemenis began to remove tent camps in the capital Sanaa and other cities in the country, declaring the end of their peaceful sit-in which was a part of revolution that forced former President Ali Abdullah Saleh to step down last year. (Xinhua/Mohammed Mohammed)

Yemeni protesters push down a wall that was used by protesters for peaceful sit-in in the Change Square in Sanaa, Yemen, on April 19, 2013. Yemenis began to remove tent camps in the capital Sanaa and other cities in the country, declaring the end of their peaceful sit-in which was a part of revolution that forced former President Ali Abdullah Saleh to step down last year. (Xinhua/Mohammed Mohammed)