Seoul: Civic groups on Monday denounced the U.S. government for its massive immigration crackdown on South Korean workers at a battery plant construction site in Georgia last week, calling for the immediate release of the detainees.

According to Yonhap News Agency, the progressive groups, including Candlelight Action and the Korean University Students Progressive Union, staged the rallies in front of the U.S. Embassy in Seoul, demanding the United States apologize for the incident. More than 300 South Korean workers are being held in a detention center in Folkston, Georgia, following a raid on Thursday at a construction site for an electric vehicle battery plant being built by a Hyundai Motor Group-LG Energy Solution Ltd. joint venture near Savannah.

"(They) call our workers building factories on American soil due to pressure from the U.S. illegal immigrants," the protesters said. "The U.S., which does not pay a single penny for the U.S. base in Pyeongtaek or its embassy in Seoul, is illegal in itself," they claimed. Another protester referred to the arrests as no different from a "hostage situation," saying the South Korea-U.S. alliance should be overhauled.

Police estimated that around 70 people joined the protests.