Police in Derry last night arrested three men in connection with the assault of a man in the city at the weekend.
The victim (38) was attacked by four men on Rosemount Avenue early on Saturday morning. He suffered severe injuries and is in a critical condition in Belfast's Royal Victoria Hospital.
All of those arrested are in their 20s. A fourth man, arrested on Sunday, remains in custody.
PSNI detectives have appealed for anyone in the area between 4.45am and 5.30am to come forward.