Lack of fuel perils humanitarian aid

The United Nations warned fuel shortages threaten to halt all relief operations in Yemen "within days" as Saudi Arabia reported the first retaliatory cross-border attack of its five-week air war.

The attack by Yemeni rebels resulted in late-night clashes that left three Saudi soldiers and "dozens" of Yemeni rebels dead, the Saudi Defense Ministry said late on Thursday.

A ministry statement said that a group of Yemen's Shiite rebels attacked "border posts and control points" in the southern Saudi province of Najran late on Thursday night. Saudi forces, backed by air force fighter jets, repelled the attack, the statement said.