Yemeni officials say at least 40 people have been killed over the past two days across the country in violence that has strained a cease-fire that started this week.

The truce is meant to pave the way for peace talks between Yemen's warring sides, due next week in Kuwait.

The officials say the fatalities resulted from airstrikes by a Saudi-led coalition, which is battling the country's Shiite rebels and their allies, and in fighting on the ground between rival groups. They say the capital, Sanaa, has been particularly hit by airstrikes.

They say a coalition airstrike Thursday in Nahm, an area east of Sanaa, killed at least one civilian and wounded five.

The officials spoke on condition of anonymity because they aren't authorized to speak to journalists.