The extremist group Islamic State has claimed responsibility for a suicide attack last week that killed seven Jordanian troops and wounded 13 on the border with Syria.

The IS news agency Amaq posted a video of the attack on its Facebook page Monday. It shows a car racing through flat desert toward an army post, followed by an orange ball of fire rising in the air close to the installation. In a separate statement, Amaq said the attack was carried out by IS.

Jordan has said it would respond with an "iron fist" to the attack.

It sealed off the border, cutting off tens of thousands of Syrian refugees stranded in the area from international aid delivery. Aid officials have said no food and little water have reached the area.