At least two people have died, including a judge, after a man believed to be a defendant in a bankruptcy trial opened fire in a Milan court.
Italian police have arrested a man believed to have shot dead two people at the Palace of Justice in Milan, the country's interior minister says.
Angelino Alfano said the "presumed assassin" was detained by carabinieri military police as he tried to flee.
Officials said the gunman was a defendant in a bankruptcy case.
The Ansa state news agency identified him as Claudio Giardiello and said one of the victims was a bankruptcy court judge called Fernando Ciampi.
The suspect was now being held at a carabinieri barracks, Mr Alfano said.
The sound of gunfire inside the Palace of Justice on Wednesday morning reportedly sparked panic, with hundreds of people pouring down stairways towards the exits while police and military police officers searched for the gunman.
"All of a sudden we heard at least three or four shots," lawyer Marcello Ilia told the AFP news agency outside the building.
"We tried to find out what was going on. There were suddenly lots of police officers who told us not to leave the room, they shut us in," he said.
"After a few minutes we came out. They told us someone in a suit and tie was armed and at large in the court."
Appeals court judge Giovanni Canzio told Ansa that the gunman had opened fire at the entrance to a courtroom before escaping to another part of the building.
It was unclear how he managed to bring a weapon into the Palace of Justice, as visitors have to pass through metal detectors.
The building is in the centre of Milan, only a few streets away from the city's cathedral and main shopping district.