A Saudi soldier has been killed in shelling from across the border in Yemen, the interior ministry announced on Wednesday. He died on Tuesday in a strike on a border guards' observation post in the Harth district of Jazan in the kingdom's south, the ministry said. Around 90 civilians and soldiers have been killed in shelling and skirmishes in Saudi border regions since March when a Saudi-led military coalition began air and ground action in Yemen against Iran-backed rebels. The coalition is supporting local forces against the Huthi rebels who seized territory, including the capital Sanaa, from the internationally recognised government. More than 5,800 people have been killed in Yemen since March, about half of them civilians, according to the United Nations.