Charities that support asylum seekers say they are documenting a number of suicide attempts among those threatened with being sent to Rwanda.

The news comes as the home secretary, Priti Patel, has announced that the first group of asylum seekers who entered the UK without authorisation will be deported to Rwanda on 14 June.

Cases include a female Iranian asylum seeker who attempted suicide and told charity workers she took this action because she believed she faced being offshored to Rwanda. She was rescued, hospitalised and survived.

A 40-year-old Yemeni asylum seeker made a video addressed to Boris Johnson and Priti Patel stating that after he arrived in the UK on 13 April and found out about Rwanda offshoring plans he had “no other choice but to kill myself”.

The Independent reported the case of an Afghan asylum seeker detained in preparation for being offshored to Rwanda. He said he had attempted suicide to avoid being sent there.

The recent death of a young Sudanese asylum seeker in Calais on 11 May is under investigation by the French authorities. His friends told charity workers he told them he wanted to take his life because he no longer wanted to live after the announcement about Rwanda offshoring.

Clare Moseley, the chief executive of the charity Care4Calais, said the prospect of being forcibly sent to Rwanda was the final straw for people who might be traumatised.

The Guardian obtained freedom of information data which reveals for the first time the Home Office’s own assessments of the widespread vulnerability of asylum seekers.

Last year alone, 17,440 asylum seekers were deemed to be vulnerable and were referred to what is known as “safeguarding hubs”. In its response, the Home Office identifies 26 different vulnerabilities which can trigger a referral to a safeguarding hub including suicide and self-harm, torture, trafficking and mental health problems.

Moseley said: “The aim of the Rwanda plan is to act as a deterrent by being even more terrifying to refugees than the journeys they make in flimsy boats across the Channel. Refugees have suffered terrible oppression. Yet our goal is to deter them using the fear of more injury and oppression. This is not the act of a civilised or compassionate nation. Little wonder that Priti Patel’s actions are driving the world’s victims to take their own lives in despair.”

Enver Solomon, the chief executive at the Refugee Council, called on the Home Office to rethink its offshoring plans.“We have been receiving a number of worrying reports from our services working directly with people in the asylum system about the devastating impact the threat being expelled to Rwanda is having on them,” he said. “We are hearing tragic stories about the severe impact on mental health, including reports of self-harm.”

PCS, the union for Home Office staff, and several refugee charities have launched legal challenges against the Home Office’s Rwanda offshoring plans.

A Home Office spokesperson said:“We take every step to prevent self-harm or suicide, which is why asylum seekers have access to a health and social care services from the moment they arrive and we have a dedicated welfare team onsite at each asylum accommodation site responsible for identifying vulnerable asylum seekers and supporting them. Everyone considered for relocation to Rwanda will be screened on a case by case basis, and nobody will be removed if it is unsafe or inappropriate for them.”