Delta police have increased their presence in the area of Sunbury Hall after a woman was sexually assaulted at a nearby park last week.

In a statement issued Monday, police said the woman was approached from behind and assaulted while walking early Thursday morning. The incident was reported Friday evening, police said.

Officers were immediately sent to the area to search for a suspect and witnesses, and the canvassing efforts continued through the weekend.

There will be a continued police presence in the Sunbury neighbourhood, officers said.

Delta police are also sharing information with other agencies in B.C.'s Lower Mainland, though they have not said whether they believe the assault is linked to any ongoing investigations.

"This is a serious allegation, but we want to remind the public that these type of assaults are very rare," the force's public affairs coordinator Cris Leykauf said.

Officers are searching for a suspect described as Caucasian and approximately 35 years old. He is around 5-10 with a medium build, short brown hair, a full beard and "thin looking face."

At the time of the assault, he was wearing a black hoodie and blue jeans.

Police are also looking for witnesses, and ask anyone who has seen any suspicious activity in the area to contact them at 604-946-4411.