A bomb squad was called in after police swooped to foil a suspected Islamist terror plot on Tuesday morning.

Four men were arrested in raids in South Yorkshire and Derbyshire and the Army's Bomb Disposal Unit was dispatched to an address in Chesterfield.

The immediate area around the property was cordoned off and residents evacuated as officers carry out searches.

Three men, aged 22, 36 and 41, were detained at different addresses in Sheffield, while a 31-year-old was held in Chesterfield.

All four were arrested on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism under Section 41 of the Terrorism Act 2000.

The suspects held on Tuesday are being questioned at a police station in West Yorkshire.

Police said the arrests were "intelligence-led and pre-planned" as part of an ongoing investigation by the North East Counter Terrorism Unit.

A total of five properties are being searched in connection with the probe - four in Sheffield and one in Chesterfield.

A police statement said: "The Army's Bomb Disposal Unit is currently attending the address in Chesterfield.

"As a precautionary measure and in the interest of public safety, the immediate area has been cordoned off and local residents evacuated while a thorough search is carried out.

"We recognise that local people may have concerns as a result of this activity. We would ask people to remain alert but not alarmed and we are grateful for the assistance and understanding of people locally."

Police added that loud bangs heard at the time officers entered the premises were part of the method used to gain access.

People living near an address in the Meersbrook area of Sheffield said they were woken at around 5.30am.

Retired Joan Miller, 63, who lives opposite the run-down house, said: "It was a very loud bang. It shook the house. I pulled the curtains and saw lots of armed men in the street, so I kept watching because that was quite extraordinary."

Tuesday's arrests came as police and MI5 tackle a terror threat that is seen as unprecedented.

In addition to five attacks that took place in London and Manchester, Home Secretary Amber Rudd revealed earlier this month that security agencies have foiled nine plots since the Westminster atrocity in March.