The teenagers who reportedly plotted to murder a teacher have been permanently excluded from Cwmcarn High School.
Gwent Police said the teenagers were arrested at the school on Thursday May 1 following concerns about their behaviour.
Police said a 15-year-old pupil, from Newbridge, was arrested on suspicion of threats to kill, possession of a bladed article on school premises and conspiracy to commit murder.
The second girl, from Risca, was arrested on suspicion of conspiracy to commit murder.
The pair have been released on bail pending further inquiries.
Maths teacher Alison Cray, 46, who was understood to have been the intended target, has also praised the school.
A spokesman on behalf of Caerphilly County Borough Council and Cwmcarn High School said: “We can confirm that concerns were raised about a pupil at Cwmcarn High School last week which were swiftly dealt with by staff and Gwent Police. Support is now in place for both pupils and staff and we would like to assure parents that all appropriate steps were taken to respond effectively to the situation. We are now helping the Police with their enquiries.
“We can confirm that the two pupils have been issued with permanent exclusions and we are currently assessing their needs before recommending appropriate educational provision for each of the girls.”