"Soldiers" of the Islamic State group carried out a deadly van attack in Barcelona on Thursday, the jihadist organisation’s propaganda outlet Amaq said.

"The executors of the Barcelona attack were soldiers of the Islamic State," Amaq said on its Telegram messenger account, without naming those it claimed were behind the attack.

Amaq said they had launched the attack in response to calls to target states taking part in the United States-led coalition battling the jihadist group in Iraq and Syria.

The terror group has frequently declared that it was behind terrorist incidents in recent years, but experts have warned their claims should be treated with caution.

At least 13 people were killed on Thursday when a driver deliberately slammed a van into crowds on Barcelona’s most popular street in what police said was a "terror attack".