VIENNA (AP) — Austrian investigators have arrested a 14-year-old who was planning an attack at a railway station in Vienna and found material that suggested he supported the Islamic State group, authorities said Wednesday.

The Interior Ministry said that the boy, an Austrian with Turkish roots, was arrested in the capital on Feb. 10 and had been radicalized online. The arrest was triggered by tips to Austrian intelligence that a supporter of IS had posted stories and videos with Islamic extremist content on several TikTok profiles.

The suspect was identified and prosecutors ordered his arrest on suspicion of membership in a terrorist group or criminal organization.

The boy had a knife in his pocket at the time of his arrest, the ministry said. During a search of his home, investigators found numerous Islamic extremist books as well as sketches of attacks with knives and machetes at a station and against police officers, and drawings of fighters with the IS flag. They also found handwritten instructions for making explosive material to serve as a detonator for a bomb.

Further material that apparently was meant to be used in making a bomb was found in the building’s basement, along with other knives. The suspect refused to testify in initial questioning.

The Interior Ministry said in a statement the intended target was the Westbahnhof, a major railway station in Vienna. It did not say when the attack was supposed to take place.

A teenager was killed and five other people were wounded in a weekend stabbing in Villach, in southern Austria, by a man with possible connections with IS.

The suspect, a 23-year-old Syrian, was arrested after the attack on Saturday afternoon.