At least four people have been killed and around 15 others injured in three separate shootings in Dallas, Texas, overnight on Halloween.

Axar.az reports, citing CNN, that Dallas Police Chief Daniel Comeaux said authorities had not established a connection between the shootings but were investigating whether they were linked.

Several people have been arrested and are being questioned as police work to identify the suspected shooters. The number of injured remains subject to change, as some victims sought medical treatment on their own.

No police officers were injured in the incidents. Authorities have asked members of the public to provide photos and videos that could help the investigation.