KIDAL, Mali (Reuters) - A U.N. peacekeepers’ camp near Kidal in Mali came under mortar fire on Thursday, the U.N. mission said, shortly before a scheduled visit by the prime minister, the first to the northern city by a top government official for four years.

Soumeylou Boubeye Maiga and eight of his ministers were due in Kidal as part of a nine-stop national tour. The city and the province of the same name, the country’s most rebellious, have been under Tuareg control since an uprising in 2012.

The delegation first visited another northern town, Tessalit, where their plane landed in a sandstorm. The storm forced Maiga to remain there and postpone his arrival in Kidal to Friday, a spokesman for his office said.

Mali’s U.N. peacekeeping mission, MINUSMA, said its camp in Kidal came under fire early on Thursday morning. There were no casualties among U.N. staff there, though international forces had been wounded in the attack.

The French army operates a separate anti-insurgent mission across West Africa’s arid Sahel region, with much of its efforts focused on Mali’s troubled north.

Mali is due to hold a presidential election on July 29, but there are concerns that widespread security problems will prevent the vote from going ahead.

Maiga’s itinerary includes other locations in the north and center that have been affected by rebellion or Islamist insurgency, including Gao, Timbuktu and Mopti.

During Moussa Mara’s visit to Kidal city in 2014, the most recent by a serving prime minister, a gun battle between the Malian army and Tuareg separatists killed at least 50 soldiers and forced state governor Sidi Mohamed Ag Ichrach to flee.

Ichrach was allowed to return to Kidal last year following a ceasefire deal signed between competing Tuareg clans, but it remains de facto under the control of separatists.

Mali descended into turmoil when Islamist fighters and Tuareg-led rebels in 2012 seized control of the country’s north.

France poured in hundreds of troops to push back the insurgents in 2013, but attacks have been spreading further south, despite the U.N. peacekeeping mission.