A miltary source said the principal of the school had also been kidnapped.
The London-based human rights advocacy organisation has expressed solidarity with the families of the children and called on Cameroonian authorities to "do everything in their power" to ensure all those abducted are freed unharmed. Militias have been trying to get the regions to secede from Cameroon.
"I would like to send a strong message to the terrorists that, yes, they have provoked, they are raping, killing, looting, abducting but they are going to face a strong powerful reaction by the powers that be, not only here in Bamenda but elsewhere in the North region", said Governor Deben.
After an intensive search, the students were released and returned to the school with their driver at 9:30 p.m. (4:30 p.m. ET) on Tuesday, according to teacher Vumesegah Peter Kogah.
The group of 42 girls and 36 boys was seized by gunmen with their school principal, a teacher and driver early Monday from the Presbyterian Secondary School in Bamenda, in the northwest of the central African nation.
While no group has taken responsibility for the kidnappings, some journalists report that separatists complain that the Cameroon school system suppresses the English-speaking system inherited from the British.
About 20 percent of Cameroon's 22 million people are English speaking.
But resentment at perceived discrimination at the hands of the francophone majority, especially in education and the judiciary, began to build.
In 2016, demands for greater autonomy grew but met with a rebuff by Mr Biya.
Separatists have since attacked troops and police, boycotted and torched schools and attacked other state symbols, prompting a brutal official crackdown.
But Biya refused any concessions and a year later, radicals declared an independent state - the "Republic of Ambazonia" - taking up arms soon after. The separatists claim that they have been marginalised in Biya's regime.
At least 400 civilians and more than 175 members of the security forces have been killed in the year to September, according to a toll compiled by non-governmental organisations.
Estimates of displaced people in the Northwest Region are not available.
More than 300,000 people have fled the violence, many of them now living from hand-to-mouth and exposed to varied dangers in the forests, and some across the border into Nigeria. Turnout in the English-speaking regions reportedly may have been as low as 5 percent.