A man in his 30s was left in a critical condition at Belfast’s Royal Victoria Hospital after suffering head injuries in a "brutal attack" in Derry.
Police said the man was kicked and punched at around 5pm on Sunday.
It is understood the assault happened just yards from the Hands Across the Divide monument at Craigavon Bridge.
A 47-year-old man arrested in connection with the incident was later released unconditionally.
Detective Inspector Adrian Burns said police were keen to speak to anyone who saw a group of men around steps which link Carlisle Road to John Street at the time of the attack or who witnessed the assault.
“This was a brutal attack on a defenceless man,” he said.
The assault has been widely condemned.
Derry independent councillor Sean Carr said people were shocked that such a serious attack could take place on a quiet Sunday afternoon.
