London - A fourth man was arrested on Thursday on suspicion of attempted murder over a hammer attack on three wealthy female Emirati tourists in their luxury London hotel room.

The attack happened at around 2:00am on Sunday in a room on the seventh floor of the Cumberland Hotel, by Hyde Park and the main Oxford Street shopping thoroughfare.

On Tuesday, officers arrested three men aged 56, 34 and 32 on suspicion of attempted murder following raids at addresses in Islington, north London.

A 31-year-old woman was also arrested in Islington on suspicion of handling stolen goods.

A fifth suspect, a 32-year-old man, was also arrested from the same borough on Thursday. All five remain in custody.

The victims were part of a wealthy family group who had come to London for shopping and sightseeing. The women had visited high-end stores on Saturday.

One of the victims remains in a critical condition in hospital. The other two women are also in hospital, but their injuries are not believed to be life-threatening, police said on Thursday.