Washington (CNN) A$AP Rocky has been held in Swedish police custody for weeks, but while President Donald Trump has been negotiating with the country to secure the New York rapper's release, Swedish officials have not given any indication the President's contact will have any bearing on the American's detainment.

Trump -- in a Saturday tweet that comes one day after the Stockholm District Court decided the Grammy-nominated rapper should remain in custody for another week while prosecutors finish their investigation -- said he spoke with Swedish Prime Minister Stefan Löfven to discuss Rocky's case. A$AP Rocky, whose real name is Rakim Mayers, is being held in prison in Stockholm pending an assault investigation tied to an incident in late June.

"Just had a very good call with @SwedishPM Stefan Löfven who assured me that American citizen A$AP Rocky will be treated fairly. Likewise, I assured him that A$AP was not a flight risk and offered to personally vouch for his bail, or an alternative," Trump tweeted Saturday.

While Trump said he told the Swedish prime minister he would personally vouch for bail for A$AP Rocky, in fact Sweden has no bail system.

Separately, Linnea Wegerstad, a lecturer in criminal law at Lund University in Sweden, told the New York Times, "Sweden does not have a system of bail and alternative ways of stopping peace leaving the country, like taking their passport, are rarely used. She added, "If you live in a country where bail is possible, I understand you'd be surprised."

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