New intelligence failings have been disclosed by Austrian officials ahead of the murder of four people in Vienna on Monday night. The city's anti-terror chief has been suspended, at his own request.

The attack was claimed by the Islamic State. The Austrians have admitted that the gunman met two people from Germany who were already under observation.

Interior Minister Karl Nehammer has spoken of "obvious, and in our view intolerable mistakes".

A gunman, later identified as a 20-year-old "Islamist terrorist" who had been released from jail in December, went on the rampage for nine minutes in the centre of Vienna, opening fire on people at bars and restaurants on Monday.

The attack, in six separate places, left four people dead and 23 others wounded, and it was finally brought to an end when the gunman was shot dead.

After the fatal shooting of two men and two women in the centre of Vienna on Monday it was revealed that the armed gunman had been released early from a 22-month jail term for trying to join Islamic State jihadists in Syria.

In a further development, a mosque and a mosque association frequented by the 20-year-old have been closed, which Integration Minister Susanne Raab said had contributed to his radicalisation.