Villagers in al-Hajawara in northern Hajjah province said multiple air bombings killed 12 people inside their homes and wounded 30 others. Residents in the southern district of Qabatiya said 7 civilians were killed in an attack on a market.
A Saudi military spokesman could not be immediately reached for comment, Reuters.
Yemen's Houthi group is fighting a civil war against loyalists of fugitive former President Abed Rabbou Mansour Hadi, who has been backed by airstrikes and ground forces from a mainly Persian Gulf Arab coalition led by Saudi Arabia.
Half of the nearly 6,000 people killed in the fighting and airstrikes are civilians, including 637 children, according to the United Nations.
A seven-day ceasefire is due to start on Monday, the day before planned UN-sponsored peace talks in Switzerland, senior officials on both sides of the civil war said.
Previous peace talks in June failed and a ceasefire the next month quickly unraveled, but months of stalemate in ground combat and reports of increased pressure by Persian Gulf Arabs' Western allies to end the war may encourage a political settlement.