SEOUL, South Korea — A Korean-American woman accused of praising rival North Korea in a recent lecture was deported from South Korea on Saturday, in the latest in a series of cases that critics say infringe on the country's freedom of speech.

The Korea Immigration Service decided to deport Shin Eun-mi, a California resident, after prosecutors determined that her comments violated South Korea's National Security Law, agency official Kim Du-yeol said.

Shin departed the country on a flight to the U.S. on Saturday evening, another immigration official said on condition of anonymity, citing department rules.

"Frankly speaking, I feel like I'm betrayed by someone who I have a crush on," Shin told reporters before her departure.

She said she hopes to be able to return to both Koreas.

The Korean Peninsula remains technically in a state of war, split along the world's most heavily fortified border, because the 1950-53 Korean War ended with an armistice, not a peace treaty. In South Korea, praising North Korea can be punished by up to seven years in prison under the National Security Law.

In Washington, State Department spokeswoman Jen Psaki said Shin had been barred from exiting South Korea for three weeks, and the U.S. has seen reports indicating the prosecution has asked for her to be deported and banned from the country for five years.

In a rare note of criticism of a key ally, Psaki said that despite South Korea's generally strong record on human rights, the security law limits freedom of expression and restricts access to the Internet.

Supporters argue that the law is needed because of continuing threats from North Korea. But critics want it scrapped. Past authoritarian leaders in South Korea frequently used the law to suppress political rivals.

Shin posted stories about her trips to North Korea on OhmyNews, a popular South Korean online news site. Her book on her trips was included in a government-designated reading list in 2013, but the Culture Ministry removed it this week. Ministry officials said they will seek to retrieve 1,200 copies that were distributed to libraries across South Korea.

During a November lecture in Seoul, Shin said many North Korean defectors living in South Korea had told her they want to go back home and that North Koreans hope new leader Kim Jong Un will bring change. She also praised the taste of North Korean beer and the cleanliness of North Korea's rivers.

Shin has said she had no intention of praising the country and was only expressing what she felt during her travels there.

Conservatives have sided with government moves to expel Shin, accusing her of ignoring North Korea's abysmal human rights conditions. But her impending deportation drew sharp criticism from liberals who say the conservative government of President Park Geun-hye is clamping down on freedom of speech.

"The decision to deport her is a clear violation of human rights," the Hankyoreh newspaper said in an editorial Friday. "The government is taking the lead in trampling on human rights."

At the United Nations, the deputy spokesman for Secretary-General Ban Ki-moon, Farhan Haq, told reporters: "The secretary-general's position on freedom of expression and freedom of opinion is well known. ... That would apply here as well." Ban is South Korean.

In October, prosecutors indicted a Japanese journalist on charges he defamed Park by reporting rumors that she was absent for seven hours on the day of a ferry disaster last April because she was with a man. Last month, the Constitutional Court ordered the dissolution of a small leftist party that officials say advocated a North Korean-style socialist system.

In December, a high school student threw a homemade explosive device toward a podium where Shin was speaking, injuring two people. Shin was not injured. The student was sent to a juvenile detention center and is awaiting trial.