The tweet was later reissued with the correct spelling of "unprecedented".
The tweet containing the error was deleted.
Both countries had been seeking to quietly resolve the delicate incident, with the Chinese foreign ministry saying it had been working behind the scenes with the US "all along".
President Barack Obama avoided passing comment at his end-of-year press conference on Friday.
Trump's message was itself an unprecedented action. President-elects usually wait until after they are inaugurated to begin making comments on sensitive diplomatic matters.
The seizure of the drone coincided with sabre-rattling from Chinese state media and some in its military establishment after
Trump cast doubt on whether Washington would stick to its nearly four decades-old policy of recognising that Taiwan is part of "one China".
His comments came after he enraged China by accepting a congratulatory call from the president of Taiwan.
The one-China principle, which has been upheld by Washington since it switched allegiance from Taipei to Beijing in 1979, has been described by China as the "bedrock" of relations between the world's two most powerful countries.
On Friday, Obama said anyone upending the one-China rule would have to be "conscious of the consequences. They will not treat that like some other issues."
The drone was taken on Thursday night, the first seizure of its kind in recent memory, about 50 nautical miles northwest of Subic Bay, off the Philippines, just as the USNS Bowditch was about to retrieve the unmanned underwater vehicle (UUV), US officials said.
"The UUV was lawfully conducting a military survey in the waters of the South China Sea," a US official said. "It's a sovereign immune vessel, clearly marked in English not to be removed from the water - that it was US property."
Meanwhile, Trump paid millions of dollars of his presidential campaign finances to his own businesses and family arising from their provision of campaign services, a review of government reports show.
The president-elect fed almost US$12.5 million to his companies and to family members duringthe 18-month election bid, reportedly running more funds through his private enterprise than any other candidate.
"I don't think we've ever seen one like this," Larry Noble, general counsel of the Campaign Legal Centre told CNN, who scoured the government reports.
