Vitriolic statement follows charity’s media conference in which it called for an end to offshore detention

The Nauruan government has accused Médecins Sans Frontières of conspiring against it and entering the country under the guise of healthcare in order to engage in political activism.

The lengthy and vitriolic statement, released on Friday afternoon, came in response to a press conference held by MSF on Thursday after it was abruptly kicked off the island by the Nauru government.

MSF called for the immediate evacuation of all asylum seekers and refugees on Nauru and a permanent end to Australia’s offshore processing policy. It also described a difficult working relationship with the Nauru government despite having been invited there late last year.

“Although MSF claimed to be a partner to Nauru and the Nauruan people, instead of working with us, they conspired against us,” the Nauruan government said.

“It is not unusual for an organisation such as MSF to gain political mileage from our decision to cease the [memorandum of understanding]. They must realise that no longer will our country accept the concocted lies told about us purely to advance political agendas.”

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MSF had detailed the growing mental health crisis among asylum seekers and refugees, including cases of resignation syndrome among children, and at least 78 patients – including children – who had attempted suicide or self harm in the last year.

They said patients had reported that Nauru’s hospital had turned people away, and that police were taking those who attempted suicide to the police station instead of the hospital. Other island sources have made similar reports to Guardian Australia in recent weeks.

However Nauru’s statement on Friday said: “The facilities, care, welfare and homely environment offered to refugees and asylum seekers on Nauru are comparable or better than what other refugees and asylum seekers across the globe receive.

“Nauruans have embraced our refugee and asylum seeker brothers and sisters and the government continues to work closely with all other stakeholders to continue this.”

The statement also used an anecdote told by MSF psychiatrist Dr Beth O’Connor – about a Nauruan official ordering her to stop assessing a young refugee child who had attempted suicide – as an example of poor conduct.

“Their focus was supposed to be the local community. To the contrary, as MSF admits, they would ‘sneak the details from the clinic’ and give them to refugees and asylum seekers ‘so they could later come and see us (MSF).’ This behaviour was common for MSF on the island in fulfilling their objectives as advocates.”

In its statement Nauru claimed the organisation was there to “devote their services to Nauruans as the refugees and asylum seekers were catered for by another international health service provider”.

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The memorandum of understanding signed between the two countries expressly states that MSF was there to treat locals, refugees and asylum seekers “without discrimination”.

The director of MSF Australia, Paul McPhun, on Thursday criticised the speed at which the charity was made to leave patients – locals and non-locals – without a medically appropriate handover or wind-down.

Staff members said they were very concerned for the Nauruan patients they left behind, some of whom were treated for serious and chronic psychiatric disorders.

He would not speculate on the reasons for Nauru’s decision, but said: “It cannot be that 11 months ago that we reached an agreement that there was a significant need for our services on Nauru … and 11 months later that gap is somehow filled.”

In response to Nauru’s statement, a spokeswoman for MSF said the organisation’s only agenda was “to provide the best medical and mental health care to Nauruan asylum seekers and refugees on the island and alleviate their suffering”.

“This was done in agreement with Nauruan authorities. What MSF found while treating refugees and asylum seekers in Nauru, is that the very cause of their suffering is the indefinite nature of the offshore detention policy. As humanitarians, we cannot ignore the devastating impact of this policy. There is no therapeutic solution for them as long as they are indefinitely trapped on Nauru.”