Turkish President Recep Tayyip Erdogan offered his condolences to families of the victims who were killed in the devastating Tezgam fire and wished a "speedy recovery to the wounded survivors".

"On behalf of my country, I extend my deepest condolences to the people of Pakistan — our friends and brothers," he said in a video message, posted from the Turkish president's official account on Friday.

Erdogan mentioned 65 victims, as was earlier reported; the number of deceased, however, went up to 73 by late Thursday.

About 73 people perished in the Liaqatpur city of Rahim Yar Khan district when three carriages of a Tezgam train caught fire on Thursday. According to initial reports, the fire was caused by a cylinder blast that occurred when passengers were preparing breakfast for themselves in a moving train.

Condolence messages were also sent by the Duke and Duchess of Cambridge, UK Foreign Secretary Dominic Raab, United States' Acting Assistant Secretary of State Alice G. Wells, the Chinese embassy in Pakistan and former British high commissioner to Pakistan Thomas Drew, among others.

"Having just returned from visiting Pakistan, we were horrified and deeply saddened to hear about the tragic fire on the Tezgam train near Rahim Yar Khan," a statement posted by Kensington Palace on behalf of Prince William and Duchess Kate Middleton said. "Our thoughts and prayers are with all the people and families affected by this heart-breaking disaster."

Raab wrote to Foreign Minister Shah Mahmood Qureshi "to express condolences on behalf of the UK" over the "tragic Tezgam train fire", the British foreign office said in a tweet.

"Our thoughts go out to all those affected and their friends and families," the tweet added.

Wells also extended her "deepest condolences" to families of victims of the "heartbreaking train accident".

A statement posted by the US State Department's Bureau of South and Central Asian Affairs' Twitter account said: "Terrible news out of Rahim Yar Khan about the heartbreaking train accident today. I send my deepest condolences to the families of the passengers and the people of #Pakistan. AGW."

The Chinese embassy in Pakistan said it was "saddened by the tragic accident" and extended "heartfelt condolences and sympathies" to the families of the victims.

"The Embassy is saddened by the tragic accident of the Karachi-Rawalpindi Tezgam Express fire that caused losses of lives in Liaqatpur near Rahim Yar Khan earlier today. Our heartfelt condolences and sympathies go to the bereaved families and we wish the injured a speedy recovery."

Sharing a news story of the incident, Thomas Drew said: "Horrific news. My thoughts are with the victims, their families and friends."