The Houthis who are Yemeni, and backed by Iran are a militant group. Their biggest demand is a free Palestine. For this, they have been blackmailing and attacking the assets of the west by different channels. They attacked ships owned by the western businessmen which travel from the red sea.
Today, after the assassination of Ismail Haniyeh by Israel, Houthis attacked a drone which was flying over the Saada governorate in north Yemen. It was an American MQ-9 reaper UAV.
Iran announced that we will launch a joined attack on Israel. Yemen, Syria, Lebanon are already at war with Israel.