The terror group Islamic State claimed responsibility Monday for one of the deadliest attacks in Jordan in years, posting a video online that it said showed a car bomb exploding near a Jordanian border post.

Last week’s blast on the Syrian border killed seven Jordanian troops, wounded 13 and exposed the pro-Western kingdom’s vulnerability to attacks by the militants who control large areas of neighboring Syria and Iraq.

Jordan has vowed a harsh response, but has not given specifics.

After the June 21 attack, it sealed 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 two border tent camps, known as Ruqban and Hadalat, since last week.

The purported attack video shows a vehicle kicking up dust as it speeds across flat desert toward what appears to be the Jordanian base. An orange ball of fire rises in the air, followed by a cloud of thick black smoke and the sound of an explosion. The video was posted Monday on the Facebook page of the IS news agency Amaq.

The footage was released after Amaq published a statement by an unidentified “source” that the attack “which hit the Ruqban American-Jordanian base inside Jordan was carried out by one of the fighters of the Islamic State.”

Jordanian government spokesman Mohammed Momani declined comment Monday.

The website “Hala Akhbar,” affiliated with the Jordanian military, carried a statement from what it said was an “official source” pledging retaliation.

“Jordanians need to know they are being targeted by these dark criminals, and the means used by this terrorist organization show its criminality and brutality,” said the statement. “It will not affect Jordan’s determination to eliminate it.”

“The fate of this gang is either Jordanian jail or being killed,” the statement also said.

The border attack came less than three weeks after an assailant killed five people in a shooting attack on a local branch of the Jordanian intelligence agency in a Palestinian refugee camp.

Jordanian analyst Saad Hattar said the two attacks laid bare Jordan’s vulnerability.

They “constitute a wake-up call to the government to stand up and not to underestimate the threat of this dangerous organization,” he said.

A precursor of IS, the al-Qaida terror network, carried out the last previous major attack on Jordanian soil — a triple hotel bombing in the capital Amman in 2005 that killed 60 people and wounded dozens.

(AP)