(CNN)At least seven officers were injured and at least three of them are feared dead in a shooting in Baton Rouge, Louisiana, a source with knowledge of the investigation told CNN.
Police received a call of "suspicious person walking down Airline Highway with an assault rifle," the source said. When police arrived, the man opened fire.

The remaining officers are hospitalized in critical condition, the source said.
Kip Holden, the mayor-president of East Baton Rouge Parish, said authorities were still trying to get a handle on the situation, but added, "The count is three officers dead possibly."
The victims may include police officers and sheriff's deputies.
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"There is still an active scene. They are investigating," he said. "Right now we are trying to get our arms around everything."
The shooter is believed to be down as well, Holden said.
"Everything is moving fast and I have not been able to verify everything," he said.