WASHINGTON (Reuters) - The fate of a dozen U.S. troops linked to a prostitution scandal in Colombia ahead of a visit by President Barack Obama will be decided within days after an investigator forwarded his recommendations on Friday to the general in charge of the region.

The military personnel and another dozen Secret Service agents were linked a raucous party last month that ultimately led to as many as 21 prostitutes being taken back to some of their hotel rooms.

The military troops and Secret Service agents were part of a task force providing security arrangements for Obama ahead of his visit to a regional summit in the city of Cartagena. The incident overshadowed Obama's visit and embarrassed the services involved.

Eight agents have left the Secret Service since the incident, one had his security clearance revoked and three were cleared.

None of the U.S. troops, who included members of all the different service branches, have been punished because officials were awaiting the outcome of a military investigation that could lead to criminal charges or administrative punishments.

The officer investigating the incident completed his inquiry on Friday and forwarded the findings and recommendations to the head of U.S. Southern Command for action, a military spokesman said.

General Douglas Fraser, the head of U.S. forces working in South America, will take several days to review the report, which will advise him whether to impose administrative punishments, pursue criminal charges or take no action at all.

Jose Ruiz, a spokesman for the Southern Command, said Fraser could approve the report, disapprove it or return it to the investigator for clarification if he has questions.

Some of the agents were sent home immediately after the incident became public. But the military personnel initially linked to the incident were confined to quarters on alleged curfew violations and remained through the presidential visit to complete their assigned tasks.

While prostitution is legal in Colombia, it is illegal for all service members under U.S. military law.

(Reporting By David Alexander; editing by Mohammad Zargham)