Kim lookalike Howard X claimed 15 officers had questioned him and Trump lookalike Russell White for almost three hours, warning them to drop their imitation act.
The pair have been making public appearances in Hanoi over the past few days, talking to media and taking pictures with amused onlookers.
In a lengthy Facebook post, the the Hong-Kong born Australian impersonator revealed he and his Canadian friend were detained by officials following a talk they gave at the state-run VTC station.
“They then said that this was a very sensitive time in the city due to the Trump/Kim summit and that our impersonation was causing a 'disturbance',” wrote Howard X, who real name is Lee Howard Ho Wun.
He said police or immigration officials had “suggested that we do not do the impersonation in public for the duration of our stay as these presidents have many enemies and that it was for our own safety”.
Howard X claimed one unnamed Vietnamese officer had threatened the mimics with deportation, saying they were breaking immigration rules.
After two and half hours of questioning, they were driven back to their hotel and told to stay put until authorities decide how to treat them, the impersonator claimed.
“Although I am not surprised that I got detained for doing my impersonation in Vietnam, it’s still pretty annoying. What it shows is that Vietnam has a long way to go before they will be a developed country and I wonder if they ever will under these conditions,” he wrote.
Mr White later confirmed the detention and also claimed they had both been threatened with deportation.
Officials told them to “stop doing the impersonation or we will kick you out of the country”, he told AFP on Saturday.
Howard X was also questioned by Singaporean immigration authorities when he and his colleague appeared in the city-state for the first Kim-Trump summit last June.
He also showed up at the 2018 Winter Olympics in South Korea, where he danced in front of an appalled North Korean cheer squad before security officials hauled him away.
The US president and North Korean are set to meet in Hanoi on 27 and 28 February for talks over the communist’s country’s nuclear weapons programme.
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