According to Kristi Noem, minister for internal security, there are several victims.
"We can confirm that there are several injured and dead", writes Noem on X.
The shooting occurred in or at an office belonging to the immigration authority ICE.
The shooter opened fire from a nearby building, writes the Dallas police on X. Two people were taken to hospital with gunshot wounds, while a third victim died on the spot, according to the police. The shooter is also dead.
According to an ICE spokesperson, two people have been killed, writes NBC News.
All the shot are reported to have been people who have been deprived of their liberty by the authority.
Preliminary information is that it was a possible sniper, said the authority's chief Todd Lyons to CNN a while ago.
In unconfirmed video clips on social media, a large gathering of emergency vehicles is seen at the scene.
The perpetrator shot themselves, says security minister Noem.
ICE, Immigration and Customs Enforcement, is a US federal police authority with the task of protecting the US against cross-border crime and illegal immigration. The authority has been given a record budget to be able to carry out President Donald Trump's promised mass deportations of undocumented migrants in the US.
"Even though we do not know the motive yet, we know that our ICE police are exposed to violence without equal. It must come to an end", writes Noem on X.
