BBC reporter Rupert Wingfield-Hayes arrived Monday evening in Beijing on a flight from Pyongyang, according to a tweet from the BBC's Asia bureau chief, Jo Floto.
North Korean officials detained Wingfield-Hayes, the BBC's Tokyo correspondent, at the Pyongyang airport, questioned him for eight hours and then made him sign a statement apologizing, according to the broadcaster.
North Korean authorities said they took issue with "disrespectful" reports he filed from inside the country last week.
Reporter 'speaking very ill' of system
Speaking on the matter at a press conference, O Ryong Il, secretary general of the North Korea's National Peace Committee, said the BBC team had violated local customs and acted in an aggressive manner during the trip.
"During their coverage they were not very just in terms of respecting the local custom, the system in the DPRK and even made distorted facts," he said, using an acronym for the Democratic People's Republic of Korea, as the country is formally known.
"They were speaking very ill of the system of the leadership of the country when they should have been reporting very fairly, objectively and very correctly."
He said Wingfield-Hayes would never be allowed back into North Korea to report.
"We think that if the BBC is a genuine, true, international media organization you should be acting in such a way as to respect the law and system in the country, and you must admit your mistakes."
Another BBC correspondent at the press conference used the word "interrogated" in relation to Wingfield-Hayes' treatment and asked how the world would view the fact that North Korea had detained and punished a journalist for reporting things with which it didn't agree.
The question remained unanswered, and the official walked out of the room.
A BBC spokesman told CNN that the organization was "very disappointed" at the deportations.
"Four BBC staff, who were invited to cover the Workers' Party Congress, remain in North Korea and we expect them to be allowed to continue their reporting."
Complete media control
North Korea's domestic media are completely state-owned and controlled.
North Koreans will never hear or see anything critical of the government -- a huge proportion of media coverage is devoted to praising the leadership.
North Korean authorities allow limited foreign media to enter the country but are sensitive about what journalists see and how they report about it.
Foreign journalists are not allowed out of their hotels except under tight government supervision. They are not allowed to choose their itineraries and are taken almost exclusively to prestige projects where there are constant reminders to "produce good reports."
The most serious offense, in the eyes of North Korean officials, is any insult or perceived disrespect of the man they call their "supreme leader," Kim Jong Un.
Wingfield-Hayes and his team were in the country with three Nobel Laureates on a trip organized by the Vienna, Austria-based International Peace Foundation ahead of the congress, along with Prince Alfred of Liechtenstein, who chairs the foundation's advisory board.
The BBC correspondent told CNN the day before his detention and subsequent expulsion that North Korean authorities had spoken to him harshly about his reporting, which had highlighted aspects of life in the capital.
"The detention and expulsion of the BBC team is a clear-cut case of violation of press freedom," said Nicholas Bequelin, Amnesty International's East Asia director.
"Amnesty International ranks North Korea as one of the most repressive environments in the world in respect to freedom of information and the presence of a few foreign journalists and media organizations should not be taken as a sign of greater freedoms in the country."
New title for Kim Jong Un
At the congress -- the first in the country for 36 years -- Kim was elected chairman of the Workers' Party (WPK).
His previous title was first secretary of the party.
Five members of the presidium of the political committee, the highest party body, were also elected.
The elevated title for Kim and new leadership lineup clears the way for the North Korean leader to pursue his strategy of simultaneous nuclear and economic development with the full support of the party.
As of Tuesday, China's President Xi Jinping was the only world leader to have congratulated Kim, a sign of North Korea's almost complete isolation internationally.
According to state-run Xinhua news agency, Xi said he hoped the people of North Korea "will achieve new accomplishments in the cause of building socialism under the leadership of the WPK headed by Kim."
In a three-hour speech to thousands of party members, Kim set a five-year plan
to revive the struggling economy. But the speech included no major policy changes or economic reforms.
Kim, who has been in power since his father's death in 2011, called for a greater focus on factory automation, mechanized agriculture and increased coal output.
He also urged greater exports of raw materials but did not address how that would be possible in the wake of heightened U.N. sanctions after this year's purported hydrogen bomb and missile tests.