Several people were injured on Friday during a shooting at a family planning center in the US city of Colorado Springs, in the state of Colorado (west), according to a police source told AFP.
"The police operation is underway," said the source, who could not confirm if there among the wounded several officers, as local media reported.
Early reports suggest that the shots come "from outside" the establishment.
The ABC reported that "three police officers were shot and there could be more victims."
He also said that the shooting was carried out by a person who "already have been contained."
Both firefighters and police in Colorado Springs, south of Denver estatal- -the capital, used Twitter to warn people of the shooting.
The family planning centers where abortions are performed, are often targets of the wrath of citizens who are against the interruption of pregnancies.