SEOUL, South Korea (AP) — Waving the national flag, the U.S. stars and stripes and shouting military-style slogans, tens of thousands of supporters of arrested former South Korean President Park Geun-hye rallied Saturday for her to be released from detention on corruption allegations.

Park was jailed Friday over allegations that she colluded with a confidante to extort money from businesses, take bribes and allow the friend to unlawfully interfere with state affairs. The Constitutional Court ruled March 10 to remove her from office after she was impeached in December.

Reflecting a nation deeply split over its future, Park's opponents held their own protests in nearby streets, celebrating her arrest and calling for her conservative policies to be erased. Seoul police used thousands of police officers and hundreds of buses to separate the two crowds, whose rallies have divided the city's streets in recent months.

Park's arrest marked a stunning fall for South Korea's first female president, who convincingly defeated her liberal opponent in 2012 thanks to overwhelming support from conservative older voters, who remembered her dictator father as a hero who rebuilt a nation devastated by a 1950-53 war with North Korea.

Gathering in streets near Seoul City Hall, Park's supporters, many of them in their 60s or older, chanted "Release President Park Geun-hye" and "Disband the National Assembly" and roared in approval as organizers accused Park's political rivals as "leftist North Korea sympathizers" and "turncoats."

"She could have avoided this all if she wanted to, but Park chose the road of a martyr," Jung Mi-hong, one of the organizers, bellowed from the stage. "She has offered to sacrifice herself to protect the constitutionalism of the Republic of Korea and a free democracy," Jung said, referring to South Korea's formal name.

Chung Kwang-taek, a protester, said that Park's opponents "ruthlessly attacked a lonely woman who dedicated herself to the country" and that she would overcome her troubles to "live forever as a historical figure."

Prosecutors can detain Park for up to 20 days, during which they are expected to formally charge her. The most damning accusation alleges that Park took tens of millions of dollars in bribes from technology giant Samsung in exchange for business favors, which would be punishable by a prison term longer than 10 years and even a life sentence if she is convicted.

Park has apologized for putting trust in her jailed friend, Choi Soon-sil, but has denied breaking laws.