OpenAI researchers warned about a potentially dangerous artificial intelligence discovery ahead of CEO Sam Altman being ousted from the company, according to reports.

Several staff members of the AI firm wrote a letter to the board of directors detailing the algorithm, two people familiar with the matter told Reuters. The disclosure was reportedly a key development in the build up to Mr Altman’s dismissal.

Prior to his return late Tuesday, more than 700 employees had threatened to quit and join backer Microsoft in solidarity with their fired leader.

The sources cited the letter as one factor among a longer list of grievances by the board leading to Altman’s firing, among which were concerns over commercialising advances before understanding the consequences.

The staff who wrote the letter did not respond to requests for comment and Reuters was unable to review a copy of the letter.