LONDON -- A 13-year-old boy has been arrested on suspicion of attempted murder after two boys, aged 12 and 13, were stabbed at Kingsbury High School in northwest London, British media said on Tuesday.

The two victims were sent to hospital, with one taken to a trauma center "as a priority." Both boys are believed to be in serious condition, according to local media.

Police said the suspect left the scene after the incident, but was later arrested in the afternoon. Officers added that a weapon believed to have been used in the attack has been recovered.

Although counter-terrorism police are currently leading the investigation, authorities have not yet declared the incident an act of terrorism.