Residents and rescue workers clear the rubble at the scene of an explosion at the Surmalu market, which specializes in the wholesale of various goods and products, in Yerevan, Armenia, on August 14, 2022. Photo: VCG

The death toll from an explosion at a bustling market in the Armenian capital Yerevan rose to six on Monday as search operations continued for people believed trapped under rubble. 

Another 61 people were injured and 15 were missing after Sunday's blast that led to the collapse of a building at the Surmalu wholesale market, Armenia's Emergency Situations Minister Armen Pambukhchyan said.

Rescue operations were continuing "very carefully" with people still believed to be trapped beneath the debris, he added. 

Pambukhchyan told reporters that video footage of the incident showed that "there can be no talk of a terrorist attack" as the fire started before the explosion. 

He said the fire spread to "pyro materials." Local media had earlier said the explosion went off at a place that stored fireworks.

The cause of the fire was being established.

The minister said that smoke and small fire could persist for several more days with lots of plastic smouldering at the scene.

Photos and videos posted on social media after the blast showed a thick column of black smoke over the market and what appeared to be a series of detonations can be heard.

Prosecutors meanwhile launched a probe into violations "on stocking inflammable goods," breaches in fire safety standards and the death of people "due to negligence."

Armenia's Prime Minister Nikol Pashinyan visited the site of the blast on Monday, according to his press service. 

In all, 200 firefighters and medical workers were sent to the scene, as well as fire engines and construction site equipment.

Rescue workers used a digger to clear away rubble, an AFP journalist at the scene reported earlier.

The wholesale market at Surmalu is normally very busy on Sunday ­afternoons, which when the blast happened.

The disaster came at a time when the country is already going through a difficult period.

Armenia, a country with around 3 million inhabitants, is still recovering from the 2020 war with Azerbaijan.

The two countries earlier this month traded accusations of violating their cease-fire agreement and launching provocation in the disputed Nagorno-Karabakh region.

Armenia and Azerbaijan have been at loggerheads over the mountainous region of Nagorno-Karabakh since 1988. 

Relations between the two countries were severed in 1993 during the first war between Armenia and Azerbaijan over the disputed region of Nagorno-Karabakh when Turkey closed the border with Armenia in support of Azerbaijan.

Peace talks have been held since 1994, when a cease-fire was agreed, but there have been sporadic minor clashes since then.

A new round of armed conflict broke out along the contact line on September 27, 2020, before Russia brokered a cease-fire on November 9, 2020.