SEOUL (Yonhap) -- A Seoul court on Tuesday sentenced a progressive lawmaker to a suspended one-year prison term for detonating a tear gas bomb in the National Assembly's main chamber in protest of the free trade agreement with the U.S.

Kim Sun-dong of the minor opposition Unified Progressive Party was found guilty of using tear gas to block the ruling party's unilateral move to put the long-pending trade pact to a floor vote in a snap parliamentary session in November 2011.

Despite his violent attempt to block the vote, the bill passed with a majority mostly due to support by ruling party lawmakers.

The Seoul Southern District Court sentenced the lawmaker to one year in prison, suspended for two years.

Following the ruling, Kim said he would appeal the decision to a higher court.

The activist-turned-politician will lose his legislative seat if the sentence is upheld through the Supreme Court.

In a separate ruling Tuesday, the court gave Rep. Kim Young-joo an eight-month prison term for promising a former official of the minor conservative Advancement and Unification Party to lend 5 billion won (US$4.62 million) in exchange for securing the party's nomination ahead of last year's April general elections.

Kim, who eventually won the seat on a proportional representation ticket for the party, is now affiliated with the ruling Saenuri Party as the two parties merged in October.

The court will soon seek consent from the parliament before deciding whether to issue an arrest warrant for the lawmaker or not.  

His detention requires parliamentary consent as lawmakers in South Korea are immune from arrest while the National Assembly is in session.