Two men have been injured in a knife attack near Londonderry city centre.
They were stabbed at John Street near Craigavon Bridge at about 1700 GMT on Wednesday night.
One man in his 20s was taken to Altnagelvin hospital with serious wounds to his throat and upper body. He is in a stable condition. The second man's injuries were not serious.
Two men aged 22 and 24 have been arrested.
A 43-year-old man was also arrested for disorderly behaviour, assaulting police and breaching a police cordon at John Street.
PSNI Inspector Jon Burrows appealed for anyone with information to come forward.
"This happened at five o'clock in the evening on a busy weekday.
"There must have been people who were driving or walking past and saw something, or maybe heard something about what happened.
"We need them to contact us so we can solve the case and bring those responsible to justice," he said.
SDLP Derry City Councillor Mark H Durkan condemned the stabbing.
"Unfortunately the John Street area has been plagued with nefarious activity for far too long.
"Just last week the council approved funding for CCTV to be installed in the area to help combat this anti-social behaviour," Mr Durkan added.
"Regrettably this is going to be of little consolation to the man who was stabbed, but hopefully it will discourage any future attacks.
"I wish the victim a full and speedy recovery and strongly appeal to anyone who witnessed this attack to pass their information onto the police immediately."