At least 18 United Nations peacekeepers were wounded in a rocket attack on a military base in Mali on Thursday. UN spokesman Olivier Salgado told Reuters that the "preliminary" toll indicated 20 people were wounded in the attack on the military base housing UN, French and Malian forces in the town of Tessalit in the Kidal region in the country’s north. Six peacekeepers from the MINUSMA mission were seriously wounded, he said. No groups have yet claimed responsibility and Mr Salgado said it remains unclear who carried out the attack. France's military said none of its soldiers were injured, <em>Reuters</em> reported. Kidal has been under the control of Tuareg rebels since an uprising in 2012, and tensions regularly flare between armed groups and the government. The MINUSMA mission has over 13,000 troops in Mali to contain violence caused by various armed groups in the north and centre of the country, including militants linked to Al Qaeda and ISIS. Some 4,500 French troops operate a separate anti-insurgent mission across West Africa’s arid Sahel region, where militants and ethnic violence is worsening. It comes a day after the UN's envoy for West Africa and the Sahel, Mohamed Ibn Chambas warned the region had experienced “a devastating surge in terrorist attacks against civilian and military targets” in recent months.