In the 2000s the government has been fighting rebel groups such as the one led by Hussein al-Houthi's Zaydi movement Shabab al-Mu'mineen, "The Young Believers". (See Shia insurgency in Yemen.) The 2011 Yemeni protests followed the initial stages of the Tunisian revolution and occurred simultaneously with the Egyptian Revolution and other mass protests in the Arab world in early 2011. The protests were initially against unemployment, economic conditions and corruption, as well as against the government's proposals to modify the constitution of Yemen. The protestors' demands then escalated to calls for President Ali Abdullah Saleh to resign. A major demonstration of over 16,000 protestors took place in Sana'a on 27 January. On 2 February, President Saleh announced he would not run for reelection in 2013 and that he would not pass power to his son. On 3 February, 20,000 people protested against the government in Sana'a, others protested in Aden, in a "Day of Rage" called for by Tawakel Karman, while soldiers, armed members of the General People's Congress and many protestors held a pro-government rally in Sana'a. In a "Friday of Anger" on 18 February, tens of thousands of Yemenis took part in anti-government demonstrations in Taiz, Sana'a and Aden. On a "Friday of No Return" on 11 March, protestors called for the ousting of Saleh in Sana'a where three people were killed. More protests were held in other cities, including Mukalla, where one person was killed. On 18 March, protesters in Sana'a were fired upon resulting in over 40 deaths and ultimately culminating in mass defections and resignations. On 23 April Saleh accepted a proposal to step down and shift control to his deputy after thirty days. The agreement included immunity for him and his family and further required the opposition to stop public protests and join a coalition with Saleh's ruling party. Reactions to Saleh's acceptance have been reserved, without the agreement formalized or accepted by both sides and with the possibility of the stand-off continuing. On 22 May Saleh had agreed to the deal only to back away hours before the scheduled signing for the third time. On 23 May Sheikh Sadiq al-Ahmar, the head of the Hashid tribal federation, one of the most powerful tribes in the country, declared support for the opposition and his armed supporters came into conflict with loyalist security forces in the capital Sana'a. Heavy street fighting ensued, which included artillery and mortar shelling (see Battle of Sana'a).