Seven people have been arrested under suspicion of supporting the banned group Palestine Action after a protest in Suffolk.

They were arrested on Sunday morning after joining a peace encampment to create a blockade outside the main gate of Lakenheath airbase. The protest was organised after media reports that a US fighter jet shot down in Iran on Friday had taken off from the Lakenheath base.

Two further people were arrested and charged with wilful obstruction of a highway on Saturday. Michelle Macdonagh, of Springhill, Stroud, Gloucestershire, and Yvan Cormier-Scott, from Elphinstone Road, Southsea, Hampshire, have both been bailed to appear at Ipswich magistrates court.

Lakenheath Alliance for Peace said: “Seven arrests were made during Lakenheath peace camp when a group of protesters stood wearing tabards saying, ‘We oppose genocide. We support Palestine Action’. More information to follow.”

The high court ruled in February that the government’s decision to proscribe Palestine Action was unlawful. However, it remains banned pending an appeal by the Home Office.

Suffolk police said: “Police have arrested seven people, five men and two women, in Lakenheath on suspicion of supporting a proscribed organisation. They have been taken to Bury St Edmunds police investigation centre for questioning.

“Suffolk police has a duty to enforce the law without fear or favour and as it currently stands, not as it might be in the future. As such, where offences are believed to have occurred appropriate action will be taken.”

More than 2,700 people have been arrested for supporting Palestine Action since it was proscribed under the Terrorism Act last summer by the then-home secretary Yvette Cooper. Many of these have been arrested for holding placards with slogans expressing support for the group.

The encampment has been in place since Wednesday and the organisers plan to continue it until Monday.

At the beginning of the protest, the encampment organisers displayed a letter to the Lakenheath base commanders, which expressed their concerns about a “disregard for international law” from the RAF and their opposition to US air force use of British bases.