An international group of six protesters from Malta, Austria, France, Belgium and England was arrested by military police on suspicion of criminal damage and associated offences at RAF Lakenheath, in Suffolk.

The protesters, who included Davida Higgin, of the Lakenheath Action Group and Norwich CND, broke in to carry out what they described as a "citizens' weapons inspection" on the 30 nuclear missiles they believe are stored on the US-controlled base.

A second group was arrested later after breaking through the fence and scattering flower seeds while trying to place a peace flag on the base.

Two more activists, a man and a woman, were arrested by civilian police outside the base on suspicion of going equipped to commit an offence and conspiracy to commit criminal damage.

Mel Harrison, a youth worker from Bungay who entered the base, said: "We feel it is not us breaking the law but the US at Lakenheath for holding these illegal weapons of mass destruction with a stated first strike policy against non-nuclear states.

"Nuclear weapons and their aftermath are indiscriminate and illegal under international law. This base should be reclaimed for peaceful purposes."

Anu Korhonen, from Finland, who offered legal support to the international protest team, said: "We have travelled to USAF Lakenheath to search for weapons of mass destruction. We are appalled at the hypocrisy of the United States, who are willing to go to war over unconfirmed WMD in Iraq while they maintain their own illegal nuclear weapons at Lakenheath and threaten to use them."

Lakenheath spokesman Master Sgt Will Ackerman said it was not policy to confirm or deny what weapons were stored on the base.

Yesterday's direct action came after a day of peaceful protest outside the airfield on Sunday, when between 50 and 100 people marched to the entrance in silence and raised anti-war banners.