EDMONTON - Police released a sketch Tuesday of a man they believe has attacked seven women late at night in the city's southeast end over the past two months.

The attacks are becoming increasingly violent, police said.

During the first few attacks, the man approached the women from behind and pushed them to the ground before running away.

However, in the most recent attack, the suspect came up from behind and choked the woman, but she managed to fight him off and scream for help, scaring the man away, police said.

In each case, the women were attacked from behind while walking alone on a sidewalk in a residential neighbourhood.

Cops say women should be careful walking alone at night in Old Strathcona and Bonnie Doon.

"This sketch has been created with the evidence we have collected thus far," Det. Rob Chan said. "I encourage anyone with information about the identity of this person to come forward to police. Small details that you think may be insignificant could actually be very helpful in our investigation."