University students invaded the U.S. ambassador's residence in Seoul on Friday using ladders to climb over the compound's wall. They charged in with signs saying they condemn the United States and urging the ambassador, Harry Harris, to "leave this land."

"What the U.S. has done is kill, rape, poison our land and threaten our people's lives," one student shouted.

The protest, seen in videos online, was related to a sharp increase in defense costs for the 28,500 U.S. forces stationed in South Korea. In February, the country agreed it would contribute about 1 trillion won — $880 million — toward the troops for 2019, an 8.2% increase from 2018. A new round of talks is expected to be held next week in Hawaii.

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As of Saturday, all the 19 students who broke into the ambassador's compound in protest remained in police custody.

A detained college student shouts a slogan in front of the U.S. ambassador's residence in Seoul, South Korea, on Oct. 18, 2019. Chun Jin-hwan/AP

Harris gave a "shout out" to police, tweeting in English and Korean about the incident and saying his cats "are OK."

"2nd incident in 13 months in Heart of Seoul," he tweeted. "This time they tried to forcibly enter my home itself."

Big shout out to Embassy guards & Seoul Metro Police Agency for responding to protesters who breached perimeter around my residence. 2nd incident in 13 months in Heart of Seoul. This time they tried to forcibly enter my home itself. 19 arrested. Cats are OK. Thanks @polinlove ! — Harry Harris (@USAmbROK) October 19, 2019

Police said on Saturday that security was heightened at his residence. The number of guards more than tripled, to 110, the Associated Press reported, citing the Seoul Metropolitan Police agency.