Two persons were charred to death and 25 injured in a major fire at the factory of pharmaceutical major Ranbaxy in Mohali (Punjab) on Wednesday night.

Rescue teams recovered two 'skeletons' from the spot on Thursday morning, police said.

"The Fortis Hospital is treating 19 patients, out of which the condition of three is critical. One of them has been put on a ventilator. Others have sustained burn injuries ranging between 45 to 75 per cent," Medical Director of hospital K V Karanjekar told PTI.

A factory spokesman said a team comprising the state Labour Commissioner, the Deputy Director, Additional Director and Joint Director of Industries was investigating the incident.

A series of explosions ripped through the production unit of the factory at 2235 IST on Wednesday setting off the fire.

Nearly 150 people were on night shift in the factory premises when the mishap occurred.

Twenty fire tenders from Ludhiana, Ropar, Chandigarh and nearby areas were pressed into service to control the blaze, which was put out shortly after midnight.

In a statement issued on Thursday, Ranbaxy Laboratories Ltd said a fire broke out on Wednesday night in a section of one of the bulk drug facilities of the company and that it was brought under control.

"All other sections of the facilities, including all production blocks, remained unaffected and continue to operate normally," the statement issued in Delhi said.

Sanjiv D Kaul, vice-president (corporate affairs, global licensing & allied business), told PTI the unit where the fire broke out was a distillation unit and was unlikely to affect production.