An assault on prison guards by two inmates wearing fake suicide belts in a maximum-security facility is being investigated as a "terrorist" attack.

The inmates attacked one officer with "improvised bladed weapons" during the Thursday morning incident at Whitemoor prison in eastern England. That guard suffered neck and head wounds before other prison staff intervened.

More:

The attacked guard and four other members of staff were treated at a hospital and discharged.

Police said the attackers were "wearing belts with various items crudely attached". They were subdued and arrested after the attack.

Deputy Assistant Commissioner Dean Haydon, the counterterrorism coordinator, said the violence was being treated as a "terrorist attack and the investigation continues at pace".

#UPDATE | We are treating yesterday's incident at HMP Whitemoor as a terrorist attack.



Two prisoners attacked a prison officer using improvised bladed weapons. Five people were injured. They have now all been released from hospital.



📰 Full Details 👇https://t.co/zaV6YS7NQG — Metropolitan Police (@metpoliceuk) January 10, 2020

UK media have identified one of the suspected attackers as 24-year-old Brusthom Ziamani, who was jailed in 2015 for plotting to behead a British soldier.

The other suspect was in prison for a violent offence, according to the reports.

In 2016, the United Kingdom announced plans to isolate individuals the government says committed "terrorism" in the name of Islam in special units in high-security jails to limit their ability to influence other inmates.

Critics have raised concerns about the effectiveness of such policies.