At least 42 people have been killed in a land feud between tribes in northwestern Pakistan, officials said on Monday, during days of fighting with machine guns and mortars. 

Inter-family feuds are common in Pakistan, but they can be particularly protracted and violent in the mountainous northwestern region of Khyber Pakhtunkhwa, where communities abide by traditional tribal honor codes. 

The Sunni Muslim Madagi and Shiite Mali Khel tribes have been fighting since Wednesday, when a gunman opened fire at a council negotiating a decades-long dispute over farmland, local police official Murtaza Hussain said.