Ireland’s president, Catherine Connolly, said she is “very proud” but also deeply worried after her sister Margaret Connolly was detained by Israeli forces while sailing toward Gaza with an aid flotilla.

Margaret, a doctor, was among several Irish activists held when Israeli troops intercepted multiple vessels carrying humanitarian aid in the Mediterranean.

The flotilla group said the activists were part of a mission to deliver aid to Gaza, while Israel called the mission a “provocation” and accused it of supporting Hamas.

The Irish government said it is monitoring the situation as diplomatic tensions between Ireland and Israel continue to rise, Politico has reported.

The detention happened while the president was on a visit to the UK, where she met King Charles and extended an invitation for a future visit to Ireland.