(CNN) -- South Korea's prime minister has offered to resign, his communications office said Monday, after failure to win parliamentary approval to stop relocation of government offices out of the capital, Seoul. Prime Minister Chung Un-chan verbally offered to resign, but President Lee Myung-bak did not accept his offer, the office said. Chung offered to resign after failure to win the parliamentary approval, a major setback to Lee's government and a sign that his party is losing clout. The president's Grand National Party has taken a beating in local elections, which analysts see as a referendum on his handling of the Cheonan incident. The South Korean naval ship Cheonan sank March 26 in disputed waters. The loss of the ship and 46 sailors raised tensions on the Korean Peninsula. North Korea has vehemently denied charges it fired a torpedo that sank the Cheonan. CNN's Roya Shadravan contributed to this report.
South Korea's prime minister offers to resign . President Lee Myung-bak declines to accept his offer . President's Grand National Party has taken a beating in the polls .