Eighteen people were injured when ice falling from a glacier hit an Arctic sightseeing ship carrying 50 British tourists, including two Scots.

Three passengers and a Russian crewman were flown to hospital in Tromso after the incident, which happened off the Svalbard Islands 300 miles north of Norway on Wednesday.

Two of the passengers have serious but non-life-threatening injuries after being thrown around on the ship when large chunks of the ice shelf broke off and collapsed into the sea.

A local authority investigation has been launched amid concern the captain of the boat could have been sailing too close to the edge of glacier at the time.

At least one passenger is believed to have sustained a head injury. Other injuries among the tourists included broken arms and legs and fractured ribs.

One casualty is in his late-60s, and the other two in their late-40s and mid-50s. Four others were being treated in hospital at Longyearbyen on the Svalbard island of Spitsbergen. Ten more were treated there for minor injuries and are back on the boat, which docked at Longyearbyen.

The ship, the Alexey Maryshev, is operated by Dutch company Oceanwide Expeditions. The passengers had booked the £2500-a-head trip through UK company Discover The World, which said the ship had been near to an ice shelf when a part of the glacier broke into chunks.

Discover the World added: "We understand some of the smaller pieces of ice and water were washed on to the deck and seven passengers were injured.

"None of them has life-threatening injuries and two were more seriously injured than the others, but they are in a stable condition and have been moved to Tromso in Norway.

"A further passenger has also been moved to Tromso overnight together with one of the crew members. The other four injured passengers suffered less serious injuries and are still in Longyearbyen Hospital in Spitsbergen.

"We have been made aware that further passengers have been taken to Longyearbyen Hospital to be treated for minor injuries.

"We have our own experienced guide on board along with the ship's highly experienced crew and expedition team."

A spokesman for the University Hospital in Tromso later confirmed that three Britons and one Russian had been admitted with "serious injuries".

Two were taken by helicopter to the emergency medical centre at around 4am with a further two arriving some five hours later.

The sysselmann (governor) of Svalbard announced that an investigation into the incident had been launched.

Stein Tore Pedersen, tourism adviser to the sysselmann, said: "We are trying to interview the passengers and the captain to find out what really happened and then we will decide what to do next."

Mr Pedersen said the local authority was alerted to the incident at around 4.30pm on Wednesday.

The company added: "We have done all possible to contact the next of kin of those passengers who were injured, and we will continue to keep in close contact with them.

"A company executive travelled to Tromso yesterday and our managing director, Clive Stacey, went to Longyearbyen to be with the remainder of the passengers."

Mr Stacey did not rule out the possibility that the boat had been too close to the glacier at the time of the incident.

He said: "We are waiting for the investigation. It seems possible that that was the case. The captain has strict instructions on that sort of thing.

"At the moment we are focusing on the passengers and their welfare. The question of compensation is something we are putting to one side at the moment."

The company said it was in regular contact with the British Embassy in Oslo, which was assisting with the situation.

Discover The World head of marketing Georgina Hancock said the rest of the passengers had been happy to stay on the boat at Longyearbyen for the rest of their trip which ends on Sunday. Relatives in the UK who would like to speak to a Discover The World representative can call 01737 214204 or 07793 267510.