Shot Fired Into Obama Campaign Office

A shot has been fired through the window of US President Barack Obama's election campaign office in Colorado, police have confirmed.

Police spokeswoman Raquel Lopez told The Denver Post that people were inside the office when the shooting happened on Friday afternoon.

No one was injured in the attack but a large panel of glass was left shattered at the office.

Ms Lopez said police have a description of a "possible vehicle of interest" near the Denver scene.

She said investigators were looking at surveillance video taken at the time of the attack.

Police declined to release other details while detectives pursue leads.

Ms Lopez said she was not aware of any previous threats against the campaign office in the Colorado state capital.

The US Secret Service, responsible for protection of presidents, referred questions about the incident to Denver police.

An Obama campaign spokeswoman declined to comment on the incident in Denver's historic 'Golden Triangle'.

Mr Obama was in Denver on October 3 for the first presidential debate against Republican candidate Mitt Romney.

The president was in Washington DC during the incident, ahead of a scheduled trip to New York.