WELLINGTON (Reuters) - New Zealand emergency services evacuated residents near what they said was a suspected gas explosion in the South Island city of Christchurch on Friday that left a house on fire and several people injured.

The city remains on edge four months after a lone gunman killed 51 people and wounded dozens in attacks on two Christchurch mosques in New Zealand’s worst peacetime mass shooting.

There was no indication that Friday’s blast had any wider security implications.

“Fire and Emergency New Zealand was called to a house on fire ... at about 10.15 a.m. after reports of a large gas explosion,” a spokeswoman for New Zealand’s fire service said.

Four fire engines, a specialist command unit and a fire investigator were at the scene, she said.

Police said in a statement initial reports suggested a number of people had been injured in the incident in the residential suburb of Northwood. Media reports said six people had been taken to hospital.

A house was on fire and police had closed roads and were carrying out evacuations following what they described as a “serious incident”.

A Christchurch hotel worker, who was not identified, told the New Zealand Herald newspaper that a sound like an explosion had shaken nearby buildings.

“It was more than an earthquake, you’d think a bomb had gone off,” the newspaper quoted the worker as saying.

Police did not identify the cause of the incident. A Fire and Emergency Services spokeswoman said a fire investigator was at the scene but did not yet have any official information about the cause.