Greenpeace has stepped up its activities against a possible war in Iraq by blocking a major UK military port.

The pressure group's flagship Rainbow Warrior dropped anchor at Marchwood, Southampton, blocking the entrance to the military supply port at about 0900 GMT Monday.

Four rigid inflatable boats were launched from Rainbow Warrior and two protesters climbed on board a military supply ship - one was arrested and one strapped themselves to the ship's mast.

"No war" slogans were also painted on the side of the ship.

Greenpeace launched four rigid inflatable boats

Over the last two weeks, several Royal Fleet Auxilary support ships have left the port.

They will support the Royal Naval Task Group headed by the aircraft carrier HMS Ark Royal.

Greenpeace said the aim of the action was to try to prevent the naval ships joining the military build-up in the Gulf.

Campaigns Director for Greenpeace, Blake Lee-Harwood, said: "We are here today to oppose a war that we believe is entirely wrong.

"If there is an attack on Iraq many civilians will suffer and it is actually more likely that weapons of mass destruction will be used as a result of the attack rather than the reverse.

It is a peaceful protest and was quickly identified as not being a terrorist threat MoD spokeswoman

Mr Lee-Harwood said: "Marchwood military port is key to supplying British military effort into the Gulf - as long as we are here stopping ships going in and out of Marchwood we will effectively stop the military build-up.

"We have put a tight string around the military artery."

Greenpeace said Rainbow Warrior had a team of 25 protesters on board.

Slogans were painted on the supply ship

A spokeswoman for the Ministry of Defence (MoD) told BBC News Online: "It is a peaceful protest and was quickly identified as not being a terrorist threat.

"The protesters are not breaking the law - Rainbow Warrior is in the approaches of Marchwood port which is not MoD property.

"MoD police arrested one person earlier today for climbing onto a jetty which is MoD property.

"The protesters are not interfering with the loading of the ship and she will sail as planned."