British counter terrorism police said Friday that they have arrested four people in connection with a break-in at a military base last week, during which two planes were vandalised.

Counter Terrorism Policing South East said in a statement that two men, 24 and 36, from London were arrested Thursday along with a 29-year-old woman of no fixed address “on suspicion of the commission, preparation or instigation of acts of terrorism.”

A 41-year-old woman, of no fixed address, was also arrested on suspicion of assisting an offender.

They remain in police custody.

The arrests relate to a break-in at the Royal Air Force base in Brize Norton, during which two planes were damaged with red paint. The pro-Palestinian activist group Palestine Action subsequently released video footage appearing to show one of the two activists who entered the base spraying the paint into a jet�s turbine engines.

The group alleged that Britain was continuing to �send military cargo, fly spy planes over Gaza and refuel U.S./Israeli fighter jets,� and condemned the country as �an active participant in the Gaza genocide and war crimes across the Middle East.�

Earlier this week, the British government said it will ban Palestine Action under anti-terrorism laws. The measure means it will be a criminal offense to belong to or support the group, with a maximum of 14 years in prison.

The group has sought to press its point with high-profile direct action, perhaps most notably in March when it targeted one of U.S. President Donald Trump’s golf resorts in Scotland, painting �Gaza is Not For Sale� in giant letters on the lawn in response to his proposal to empty the Gaza Strip of its Palestinian population.

The government said a draft order for the ban will be laid in Parliament next week. Lawmakers still need to approve it.

Britain’s government has proscribed about 80 organizations, including Hamas and al-Qaida, and far-right groups such as National Action.

(AP)