Lee's visit came as a standoff between his ruling Grand National Party (GNP) and opposition parties over the long-delayed agreement showed no sign of easing. Opposition lawmakers have blocked GNP attempts to approve the deal since it sailed through the US Congress last month. Activists, workers and farmers have meanwhile demonstrated in the streets and police have used water cannon to disperse some protests. The president's office said Lee hoped to hold talks with parliamentary speaker Park Hee-Tae, GNP chairman Hong Joon-Pyo and Sohn Hak-Kyu, head of the main opposition Democratic Party. It was the president's first visit to push a specific piece of legislation since he took office in February 2008. The GNP has a solid parliamentary majority, but is reluctant to ram the bill through and provoke physical clashes for fear of a voter backlash before next year's general and presidential elections. The main point of contention is an "investor-state dispute" settlement system that allows disagreements between investors and the state to be settled under the mediation of a third party. Opposition parties say it could infringe the country's legal independence. The government says such a system is a global standard and is part of earlier South Korean trade pacts. The ruling party accuses the opposition of hypocrisy for trying to block a deal originally signed in 2007, when it was in power. The deal was modified ast year to address complaints from US automakers.