A gas-pipeline fire in the southern Indian state of Seemandhra has killed at least 13 people, according to the company that owns the pipeline, although the fatality figure could change.

India's petroleum and natural gas minister, Dharmendra Pradhan, said it is unclear what caused the rupture in the pipeline, which sparked a fire that engulfed a nearby dhaba, or local eatery, in flames.

The blaze took place in Nagaram village, East Godavari district, in Seemandhra, one of two new states formed earlier this year by the bifurcation of Andhra Pradesh.

"A high-level commission of enquiry" has been formed to investigate the incident, Mr. Pradhan told The Wall Street Journal, adding that he was traveling to the scene himself.

A spokeswoman for state-run pipeline company GAIL Ltd., which owns the pipeline, said the line provides natural gas to a power plant in the town of Kondapalli.

Indian Prime Minister Narendra Modi tweeted condolences to the victims. "I have spoken to [the] petroleum minister, cabinet secretary and GAIL['s] chairman and asked them to ensure immediate relief at the accident site," the prime minister said in one of his tweets.

Write to Prasanta Sahu at prasanta.sahu@wsj.com