At least 192 people are missing and 75 are dead as a result of the explosion of the Fuego volcano in Guatemala on Sunday, officials say.

Villages on the slopes were buried in volcanic ash and mud.

Rescue work on Tuesday was disrupted when a new eruption sent hot gas and molten rock streaming down the volcano's south side.

More than 1.7 million people have been affected by Sunday's eruption, with more than 3,000 evacuated.

Tuesday's explosion took many by surprise after volcanologists said the eruption, which had sent ash up to 10km (33,000ft) into the sky on Sunday, was over for the near future.

Eddy Sanchez, the head of Guatemala's National Institute of Seismology, had predicted "no imminent eruption over the next few days".

Why were so many people killed in the initial eruption?

Disaster Relief Agency chief Sergio Cabanas told AFP news agency that 192 people were unaccounted for.

No evacuation alert was issued before the volcano erupted on Sunday, said Sergio Cabañas, the director of Guatemala's disaster prevention agency.

He said that local residents had received training in emergency procedures but were not able to implement them because the initial volcanic activity happened too fast.

Sunday's blast generated pyroclastic flows - fast-moving mixtures of very hot gas and volcanic matter - which descended down the slopes, engulfing communities including El Rodeo and San Miguel Los Lotes.

Volcanologist Dr Janine Krippner told the BBC that people should not underestimate the risk from pyroclastic flows and volcanic mudflows, known as lahars.

"Fuego is a very active volcano. It has deposited quite a bit of loose volcanic material and it is also in a rain-heavy area, so when heavy rains hit the volcano that is going to be washing the deposits away into these mudflows which carry a lot of debris and rock.

"They are extremely dangerous and deadly as well."

Source: BBC