A district commander and a sergeant in Saudi Arabia's border guard have been killed in an attack launched from across the frontier with Yemen, the Saudi interior ministry said yesterday. The men were killed by heavy gunfire from the Yemen side of the border on Friday after their patrol vehicle was hit by a mine explosion, the ministry said. Saudi Arabia has been fighting Iran-allied Houthi rebels in Yemen for six months and has led a coalition of Arab states on a military campaign to eject the group from the capital Sanaa and restore the government from its exile in Riyadh.