The transfer of power on Twitter didn't go entirely smoothly.

CEO Jack Dorsey apologized Saturday for inadvertently signing up about 560,000 users to follow accounts controlled by the Trump administration, including the @POTUS Twitter handle after it switched over to President Trump.

Dorsey said the issue has been corrected.

He explained in a series of tweets that users who followed President Obama's new handle -- @POTUS44 -- after noon on Friday were automatically set to follow the Trump-run @POTUS handle.

In addition, "some people who unfollowed @POTUS in the past were mistakenly marked to now follow @POTUS," Dorsey said via Twitter. "This also affected other official Administration accounts like @VP, @WhiteHouse, and @PressSec."

We believe this affected about 560,000 people. This was a mistake, it wasn't right, we own it, and we apologize. No excuses. — jack (@jack) January 21, 2017

The social media platform began investigating complaints from users on Friday who said they were unwittingly added as followers of the account after the Trump team took it over.

The complaints created an unexpected headache for Twitter, which had carefully planned for the handover of handles for official accounts.

I'm still asking you to believe - not in my ability to bring about change, but in yours. I believe in change because I believe in you. — President Obama (@POTUS44) January 20, 2017

Under the Twitter transition, all of the official tweets from the Obama administration were removed and archived on a set of newly created accounts, including @POTUS44, @VP44 and @FLOTUS44.

People who were following @POTUS and other key accounts under Obama will automatically be following the archived accounts and the official accounts of Trump and his administration -- at least until they opt out.

But some users insisted they had found themselves following Trump's @POTUS even though they hadn't followed the account under Obama.

@Support How is it migrating when I wasn't following them? — ZACH JOHNSON (@zmjohnson) January 21, 2017

"You added @POTUS and @FLOTUS to me; I'd never followed either acct before," said the user @ZenHeathen in a response to the Twitter support post.

In his interactions with upset users, Dorsey said the switch "should have only migrated followers of original POTUS."

Trump's team, meanwhile, has been putting his new @POTUS account to use.

January 20th 2017, will be remembered as the day the people became the rulers of this nation again! https://t.co/n6aMK1MCRC pic.twitter.com/YVXQYqt9uR — President Trump (@POTUS) January 21, 2017

By early Saturday, it had tweeted four times with photos from the inauguration.

Its sole retweet was of a post by @realDonaldTrump, the personal account Trump has been using for years.

On Saturday morning, both @POTUS and @POTUS44 had 14.2 million followers. By the afternoon, @POTUS44 had 14.3 million, while @POTUS stayed at 14.2 million.

-- CNN Tech's Seth Fiegerman contributed to this report.