Investigations into why tourists were allowed to visit New Zealand’s White Island volcano before it erupted could take at least a year and result in criminal charges and jail sentences, Jacinda Ardern said.

“There remains now questions to be asked and questions to be answered,” the prime minister told reporters at her weekly press conference in Wellington after leading the country in a minute’s silence for the dead and injured at 2.11pm — the time the White Island volcano erupted on Monday last week.

Four men have been arrested in raids leading to the seizure of several vehicles in an ongoing operation.

Authorities have now revealed the company boss could have been singled out over his expensive watch and followed from Ezeiza Airport by a ‘large gang’.

An internet block was implemented in the area on Sunday night and remained in place on Monday in an attempt to quell the mounting unrest.

By Monday the protests had spread to university campuses in the cities of Mumbai, Hyderabad, Bangalore, Chandigargh and Kolkata, while in Lucknow students pelted police with stones after they fired teargas at demonstrators.

President Aoun was expected to name the current caretaker prime minister Saad Hariri, who resigned from the post on 27 October, to assume the post again at the head of a government that would include technocrats.

But protesters opposed to such a move turned out in force on Saturday, prompting the violent clashes seen in downtown Beirut.

The train company later confirmed the climate activist had travelled first class between the cities of Kassel and Hamburg.

Greta said she had only been able to get a seat after Göttingen, more than four hours into her journey, before having to change in Hamburg for a further train to Sweden.