The Carlist siege of Bilbao began on February 21, 1874, with the entrenchment of the Carlists in the hills around Bilbao, and the cutting-off of the government supply line and communications along the Ibaizabal River. Carlist besiegers, led by Joaquin Elio and Carlos VII himself, numbered around 12,000 men, and faced 1,200 government forces in addition to citizens of Bilbao recruited to serve as auxiliaries. Bombardment of the city began the same day, with Carlist artillery opening fire from their positions in the hills near Bilbao. The initial objectives were civilian structures such as food stores, bakeries and markets which provided food to the besieged citizens. Trying to undermine the determination and willingness of the citizens to resist, the Carlists continued with the bombardment until mid-April, when the attempts of lifting the siege by the government army under Serrano forced Carlists to divert attacks to the liberating army and cease the bombardment of the city.