Yemen-based Houthis — the last of Iran-backed groups still fully present in the regional war that began 14 months ago — are slowly escalating attacks on Israel with an eye to avoid full-out retaliation.

The Israeli military said the airstrikes targeted infrastructure that the Houthis have used to bring Iranian weapons and officials into Yemen.

The air assault, Israel’s fourth in Yemen over the past year, comes a week after Israeli fighter jets flew more than 1,000 miles to bomb sites in the country, including in Sana and on the port city of Salif. The Israeli military said it had struck infrastructure like power plants, as well as fuel and oil tanks.