Swedish police said on Tuesday five people were shot in an attack at a school in the city of Orebro some 200 km (125 miles) west of Stockholm, triggering a massive response by rescue services.
"Five persons are confirmed shot," police said in a statement, adding that the extent of any injuries was unclear.
"This is currently seen as attempted murder, arson and aggravated weapons offense," the police said.
Ambulances, rescue services and police are onsite, a spokesperson for local rescue services said.
The shooting took place in a campus area where several schools, for both children and adults are located.
Police said students were held indoors at the affected school and also at nearby schools.
"The news of an attack at Orebro is very serious," Justice Minister Gunnar Strommer told public broadcaster SVT, adding that the government was in close contact with police.
Police also told Reuters that no officers were injured in Orebro.
Several people were killed in a school shooting, Aftonbladet and broadcasters SVT and TV4 reported, citing anonymous sources, and stated that a police spokesman said he could not comment on the information that several people had been killed.