Two FBI agents have been shot dead and three injured during an early morning raid in South Florida, authorities have said.
The five officers were attacked at around 6am on Tuesday, while serving a court-ordered search warrant in a child exploitation case, the FBI said in a statement.
The subject of the warrant also died during the standoff, in which he barricaded himself inside a home in a neighbourhood in the Fort Lauderdale suburb of Sunrise.
None of the victims have been identified, and two of the three wounded agents are in a stable condition at nearby hospitals while the incident remains under investigation.
Law enforcement agencies swarmed the neighbourhood in the aftermath of the shooting, and police urged local residents to stay indoors for hours.
Another large contingent of officers gathered outside one of the hospitals, according to reports.
Acting Attorney General Monty Wilkinson has been briefed on the shooting and is closely monitoring the situation, a Justice Department spokesperson said.