In 1802, 12,000 Wahhabis sacked Karbala in Iraq killing up to 5,000 people and plundering the Imam Husayn Shrine. By 1805, the Wahhabis controlled Mecca and Medina. The Wahhabis also attacked Ottoman trade caravans which interrupted the Ottoman finances. The Saudi amir denounced the Ottoman sultan and called into question the validity of his claim to be caliph and guardian of the sanctuaries of the Hejaz and the Ottoman Empire, suspicious of the ambitious Muhammad Ali, instructed him to fight the Wahhabis, as the defeat of either would be beneficial to them. Tensions between Muhammad Ali and his Albanian troops also prompted him to send them to Arabia and fight against the Wahhabi movement where many died.