Debris from missiles fired by Houthi rebels caused a fire on a university campus in southern Saudi Arabia, the Saudi-led coalition fighting the Yemeni rebels said. Saudi air defences intercepted five missiles and four armed drones launched by the rebels towards the southern city of Jizan, coalition spokesman Brig Gen Turki Al Malki said. Debris from the intercepted attack started a small fire on the campus at Jizan University which was put out without causing casualties, Brig Gen Al Malki said in a statement released on the Saudi Press Agency. The attacks were carried out between Wednesday evening and Thursday morning and launched from Saada province in Yemen, he said. The northern province bordering Saudi Arabia is a stronghold of the Iran-backed rebels, who seized the Yemeni capital, Sanaa, in late 2014. Brig Gen Maliki condemned the escalating Houthi attacks on Saudi civilian targets, warning that these "hostile acts constitute war crimes". Saudi Arabia has reported numerous drone and missile attacks attacks by the rebels on its oil facilities, airports and other civilian targets in recent months. The rebels have escalated their attacks despite international pressure to find a political solution to Yemen's civil war. The UN's envoy to Yemen, Martin Griffiths, on Tuesday urged armed groups in the country to <a href="https://www.thenationalnews.com/gulf-news/un-envoy-calls-for-ramadan-pause-to-yemen-s-bitter-conflict-1.1203055">silence their guns</a> for a Ramadan respite to the devastating conflict. Mr Griffiths said the holy month offered an “opportunity for all of us to come together, think of those who are suffering, and overcome our differences”. Tens of thousands of people have been killed and millions displaced by the war, which has created what the UN describes as the world's greatest humanitarian disaster.