Fighting between pro-Saudi forces and the Shi’ite Houthis in Yemen centered around the Maarib Province today, with at least 20 civilians killed and dozens wounded when the Houthis fired Katyusha rockets which hit a crowded marketplace in the provincial capital.

Earlier in the day, seven Houthis were killed in an attack by Saudi Apache helicopters in the city, the first time the newly deployed attack helicopters have been used in combat. The pro-Saudi forces vowed to take all of Maarib and Jawf Provinces soon, and move on against the capital of Sanaa.

This just adds to the scores of civilians killed this week, with the fighting in cities leading to both sides hitting heavily populated areas repeatedly. International human rights groups have admonished both sides to avoid targeting civilians so often in the conflict.

While thousands of civilians have been killed in the war so far, the far bigger toll could be on the horizon, as months of naval blockades leave basic food and other goods in shorter and shorter supply, and leaving much of the country on the brink of famine.