At least four UN troops were killed and six seriously injured when a convoy of Chadian peacekeepers hit a land mine about 20 miles outside of Kidal. In separate attacks yesterday, mortars were fired at a UN base in Aguelhok, and four UN civilian contractors were injured by a landmine. A UN spokesman said attacks in the area have been increasing. Al Qaeda in the Islamic Maghreb’s Sahara branch recently claimed four attacks carried out in Timbuktu in July and August.