The Islamic State (Isis) has claimed responsibility for the attack on Jordanian troops near a makeshift refugee camp in Rukban area, in which six Jordanian soldiers were killed on a truck at the Jordan-Syria border.

Soon afterwards, Jordan announced closure of the northern and northeastern borders with Syria.

The militant group that had threatened to "break down" Jordan's borders issued a statement on Sunday (26 June) saying that one of its fighters carried out the 21 June suicide attack.

The suicide bomber had driven a truck loaded with explosives and detonated it at an army post near the remote area of Rukban. The area is part of the US-led coalition that has waged a war against IS (Daesh). The suicide attack, in which about 14 security personnel were also injured, was reportedly the first such attack in Jordan since the conflict in Syria began in 2011.

The jihadist-linked news agency, Amaq, reported on its website that the attack against "the Jordanian-American base at Rokban in Jordan was carried out by an Islamic State fighter".

The Jordanian army earlier said that the suicide bomber came from the makeshift Syrian refugee camp near the Rukban crossing and then entered the Jordanian territory through an opening, which is usually used for humanitarian aid deliveries.

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After closing the borders, the army warned, "We will deal firmly with any vehicle of individual that moves in the area without (prior authorization) because they will be considered enemy targets."

King Abdullah had also said that he will deal with such terrorist acts "with an iron fist".