Hajjaj besieged Mecca on 25 March 692 and reinforcements under Tariq ibn Amar arrived a month later.[22] Supplies to the city were cut off, resulting in a food shortage. The city was bombarded from the nearby mountain of Abu Qubays using catapults. The bombardment continued during the Hajj rituals.[23] According to an account by the 9th-century historian Baladhuri, the bombardment was halted during the pilgrimage at the request of Abd Allah ibn Umar, an influential son of the second caliph, Umar I.[24] Enraged by Ibn al-Zubayr's refusal to allow him to perform the tawaf (the circumambulation of the Ka'aba), Hajjaj directed catapults to fire on the Ka'aba itself.[16] According to historian Abd al-Ameer Dixon, however, only the part of Ka'aba which had been altered by Ibn al-Zubayr (see Aftermath) was targeted.[25] A sudden thunderstorm provoked fears of divine wrath among his soldiers and they stopped the bombardment.