Three of five sitting lawmakers accused of taking bribes have been detained to face further questioning, court officials said Friday, hours before the National Assembly was called into session at midnight.

Reps. Kim Jae-yun of the main opposition New Politics Alliance for Democracy (NPAD) and Cho Hyun-ryong and Park Sang-eun of the ruling Saenuri Party were put behind bars after a Seoul court issued warrants for their detention on Thursday night.

The Seoul Central District Court, however, dismissed the prosecution's request to issue arrest warrants for Reps. Shin Hak-young and Shin Geh-ryeun of the NPAD, who are being investigated in separate bribery cases.

The arrest warrants were issued minutes before the unicameral parliament was called into session at midnight. Under South Korean law, lawmakers are immune from arrest while the parliament is in session.

Cho is under suspicion of taking bribes worth 160 million won (US$156,000) from railway parts supplier Sampyo E&C in return for awarding the private company contracts since August 2008, prosecutors said.

Kim, Shin Hak-yong and Shin Geh-ryeun have also been under investigation since early August over corruption allegations.

Kim and Shin Geh-ryeun are each accused of taking about 50 million won in bribes from a local vocational training school earlier this year in return for helping pass a bill in favor of the school, prosecutors said.

The passage of the bill to revise the vocational education law in April helped change the name and upgrade the status of what is now known as Seoul Art College.

The prosecution alleges that Shin Hak-yong, the chairman of the National Assembly's education and culture committee, proposed a law governing privately run kindergartens after taking some 38 million won from an association of private kindergartens.

He is also accused of taking 15 million won from the chairman of Seoul Art College, prosecutors said.

Saenuri Party legislator Park Sang-eun is under suspicion of taking more than 600 million won from his former employer, TS Corporation, in violation of the political funding law and covering up his illegal funds, they added. (Yonhap)