Police equipped with inflatable dinghies and an underwater search team have arrived in north Wales where campaigners from Greenpeace are continuing a protest on board a US cargo ship.

Greenpeace protesters ambushed the ship carrying 60,000 tonnes of genetically modified soybeans off Anglesey on Friday morning.

The bulk carrier Iolcos Grace, which had been heading for Liverpool, was awaiting the arrival of a pilot to guide her into Liverpool Docks.

As the ship remained at anchor a group of Greenpeace volunteers boarded the ship from inflatable dinghies.

The action is part of a campaign to prevent GM crops being imported into the UK and it is believed the environmental group had been planning it for some time.

Five protesters are believed to be on board - two chained to the ship's anchor. A tent has been suspended from the ship's bow to protect the protestors chained to the anchor.

"We managed to come alongside the ship with a pole and managed to attach a ladder," explained Greenpeace volunteer Sarah North.

"As soon as they were on board the situation was very peaceful."

Greenpeace spokesman Jim Thomas confirmed that the ship was boarded at 0740GMT.

A banner has been placed on the front of the ship emblazoned with the words "Europe says no to GM".

Food chain

Greenpeace says that they are not going to allow the ship to continue with her journey while she is carrying the GM grain which they claim was destined for the food chain.

Specialist police teams with two inflatable dinghies are now on standby at Amlwch.

"There are safety issues involved here, not only for the crew, but for the protestors," said North Wales Police Chief Inspector John Hughes Jones.

"We have a number of options, but currently we're just monitoring the situation and trying to get a picture of what's happening out there."

Holds locked

The soybeans were being carried for agriculture giant Cargills, who has admitted that some of it is likely to contain genetically modified produce.

Geraldine O'Shea, a spokeswoman for Cargill UK confirmed that the cargo was a mixture of genetically modified and conventionally produced soybeans.

"It's all legal and has already been tested for safety so we're surprised Greenpeace has taken this action," she said.

The protesters have asked for samples of the cargo, but claim the captain has refused and locked the holds.

Greenpeace activist Sarah North speaking to reporters from a boat near the ship said: "It is a very civil situation but at the moment there is a standoff going on. We have contacted the company to ask them to tell the skipper to give us access."

The ship is unable to lift anchor to continue on its journey as this would injure the protestors.