Prosecutors seized three computer servers of the minor opposition Unified Progressive Party (UPP), an official said Tuesday, a step expected to speed up their investigation into allegations of a rigged primary.

The raid took place early Tuesday morning in a company managing the party's computer servers after an 18-hour standoff between police and party officials, said Lee Jeong-mi, a spokeswoman of the party's reformist emergency committee.

The servers are expected to provide information to the prosecutors on the party members and the computer program used in the primary.

Kang Ki-kab, the chairman of the reformist emergency committee, expressed concern that prosecutors could use the servers as a tool to oppress the five-month-old party created through the merger of the Democratic Labor Party and other minor liberal political groups.

Kang said in an interview on local BBS radio that one of the servers has information on more than 200,000 people who either joined or bolted from the UPP and its former predecessor over the past 13 years.

Still, prosecutors pulled back its investigators from the party's headquarters as some 100 party officials were blocking them from carrying out a separate raid.

Television footage showed Monday that several dozen party officials locked themselves inside a room in the party's headquarters as police and prosecution officials were standing outside the room's glass door.

The party "strongly condemns prosecutors for unprecedented violence that tramples on basic rights of a political party's activities," Lee said.

She also warned that her party will not sit idle on the raid and will strongly deal with prosecutors, though she did not elaborate on the details.

Meanwhile, the Supreme Prosecutors' Office said it will punish those who are responsible for obstructing the raid and using violence against prosecution officials. Currently, four party officials were being held for using violence to thwart the raid, according to prosecutors.

Prosecutors also said they will thoroughly look into the alleged primary fraud and violent clashes during the party's central committee conference earlier this month.

The raid came three weeks after the party announced that the primary designed to select its proportional representation candidates for the April 11 elections was rigged. It also comes amid deepening factional infighting over how to revive the left-wing party.

Kang said the emergency committee will hold a meeting later Tuesday to decide the fate of two other lawmakers-elect accused of being involved in the rigged primary.

Lee Seok-gi and Kim Jae-yeon, who were both convicted of engaging in pro-North Korean activities in the past, rejected the committee's previous ultimatum to step down by Monday.

Kang said the committee could expel Lee and Kim from the party, a move that will make them independent lawmakers-elect. (Yonhap)