Airstrikes on Yemen's northern province of al-Jawf killed at least seven civilians on Wednesday, residents and an official from the Houthi movement said - the third such incident since June as violence resurges in the war-ravaged country.The Houthi health ministry spokesman said air raids by a Saudi-led coalition hit residential houses in the al-Hazm district, killing nine people including two children and two women. Two residents told Reuters seven people had been killed. The coalition did not immediately respond to a request for comment. The alliance intervened in Yemen in March 2015 soon after the Iran-aligned Houthi movement ousted the Saudi-backed government from power in the capital Sanaa.Violence has picked up since the expiry in late May of a temporary ceasefire prompted by the coronavirus pandemic, with the Houthis repeatedly staging missile and drone attacks on Saudi cities and the coalition retaliating with airstrikes.Earlier this week the Houthis targeted Saudi border cities with missiles and drones in what they called a response to airstrikes that killed 10 civilians in the Hajjah region. The coalition later said it would investigate the matter.In June, an airstrike killed at least 12 people, including four children, in Saada province, according to the Houthis and a UN official. The coalition said it had targeted a vehicle carrying armed Houthi combatants.The United Nations last month removed the Western-backed coalition from a UN blacklist several years after it was first accused of killing and injuring children in Yemen.The conflict, largely seen in the region as a proxy war between Saudi Arabia and Iran, has killed more than 100,000 people and caused what the United Nations describes as the world's largest humanitarian crisis. The Houthis say they are fighting a corrupt system.