The 23-year-old woman was set upon as she walked along the street at 3.30am yesterday and pulled into adjacent Royal Park Terrace Gardens.
Police later detained two men who are “assisting” officers with their inquiries.
Officers sealed off the woodland yesterday morning for a forensic examination to take place as the investigation continued. Police also called on potential witnesses who saw anything suspicious in the area at the time to get in touch.
The area around the top of Leith Walk and London Road is used by revellers walking home after nights out in the city centre, and the vicinity has often been the site of violent attacks.
City centre councillor Joanna Mowat said temporary CCTV could be one measure used to try to increase safety in the area.
“We need to be doing everything we can to ensure the safety of residents, and so if there have been a number of attacks in this area we should look at what can be done,” she said. “Getting temporary CCTV in there is one measure which could be used quite quickly, and may act as a deterrent.”
Councillor Maggie Chapman, who represents the Leith Walk ward, said: “This is an awful thing to happen to this woman.
“There are a couple of taxi ranks in the area at the top of Leith Walk but often people may choose to walk home, perhaps because they don’t have the money.
“I would hope that the police try to have extra patrols in this area, especially at the time when nightclubs are closing. But I hope incidents like this do not frighten others from walking there at night. It’s terrible when something like this happens but the presence of people can be a deterrent and offer greater security.”
A police spokesman said: “Lothian and Borders Police are investigating following a report of sexual assault in London Road at around 3.30am yesterday.
“Inquiries are at an early stage and anyone who remembers seeing anything suspicious in the area is asked to contact police immediately.
“Two men have been detained and are currently assisting police with their investigation.”
The number of sexual assaults in the city centre rose by 37 per cent between last April and March to 56, compared with 41 for the previous year.
In September last year, a 67-year-old woman was crossing over from London Road to Brunswick Street when she was assaulted by a mugger.
In May last year, a 33-year-old man was seriously injured in an unprovoked attack by a gang of four men as he walked alone towards London Road.