The assailant blew up a vehicle at a checkpoint on the outskirts of Al-Qaim, one of the last towns in Iraq to be recaptured from IS, near the Syrian border.

Five members of the security forces were among 11 people killed in the blast, which also wounded 16 other people, mostly civilians, police Captain Mahmud Jassem told AFP.

IS said in a statement that it carried out the attack, which it claimed had left 50 people dead or wounded.

Al-Qaim, around 340 kilometres (215 miles) from Baghdad, was retaken from IS in November last year.

One month later, Prime Minister Haider al-Abadi declared victory over the jihadists.

But since then, the security forces have announced a number of campaigns to flush out holdout IS fighters from sparsely populated areas from which they have continued to mount attacks.

Iraq's security services said the vehicle used in the attack had been rigged with explosives in a desert area on the edge of Syria.

The attacker drove past two roadblocks before detonating the bomb at a third checkpoint after security forces opened fire.

The latest bombing is intended by IS to send a message that "we can act quickly and strike wherever we want", said Hisham al-Hashemi, an expert on radical Islamist groups.

He said the jihadists had chosen the area because of its strategic location on the border and the presence of US and French forces belonging to the international coalition against IS.

The vast desert that straddles the frontier with Syria on either side of the Euphrates valley town of Al-Qaim has been one of the jihadists' principal hideouts.

Hashemi said about 2,000 IS jihadists are still active in Iraq including around 100 foreigners whose objective is "to take revenge on thoe who have driven them out".

On the Syrian side of the border, offensives by forces loyal to President Bashar al-Assad and a US-backed coalition have pushed IS jihadists out of most of the territory they once controlled.

In a purported new audio message released last week, IS leader Abu Bakr al-Baghdadi called on his followers to "not give up the jihad against their enemy".

Baghdadi was thought to have been killed several times, and the US has offered up a $25-million (21.5-million euro) reward for information leading to his capture or death.