Counter-terrorism police have been granted more time to quiz three men and a 17-year-old boy arrested over a suspected Islamist terror plot.

A 27-year-old man was bitten by a police dog during an armed raid after police swooped on three addresses across London and Leicestershire on Thursday.

The suspect was held at an address in east London, while a 17-year-old boy and a 31-year-old man were arrested at another property nearby, and a 32-year-old man was arrested in Leicestershire.

Police said no shots were fired during the two armed raids in the capital, but the 27-year-old man was bitten on the foot by a police dog.

He was taken to hospital, where he remains being treated for his injuries, the force added.

All four suspects 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 other three men are being held in police custody, while officers search a number of addresses.

Scotland Yard said on Friday that it had been granted warrants of further detention for the four men allowing them to be held next week.

Officers were still searching four addresses in east and south London, it added.

The Met said that a search at an address in Leicestershire was now complete, but another at a second address in the area was ongoing.

Sources told the PA news agency the raids were part of an intelligence-led operation over a suspected Islamist plot.

Uniformed officers were seen outside Frank Slater House in Green Lane, Ilford, and nearby Ilfracombe Gardens on Thursday night.

Video footage on social media showed armed officers swooping on both addresses, with the Met’s Redbridge Borough Twitter account saying police activity in Goodmayes, east London, was related to the terror arrests.

In one video, loud bangs were clearly audible as officers near a block of flats shouted, urging people to “stay inside”. Armed police and later forensic teams could then be seen outside the block.

In what is believed to be a separate raid nearby in Ilfracombe Gardens, armed officers were seen at the front door of a house – with one officer telling those inside to “walk towards me slowly” and “place your hands on your head”.

A man was then filmed leaving the house with his arms raised, and was swiftly held against the front of the property by officers before being led down the street.