Polls suggest that LDP leader Taro Aso is deeply unpopular
Japan's Prime Minister Taro Aso has apologised to legislators of his ruling party, after dissolving parliament to hold an early election for 30 August.
He apologised for a series of defeats his Liberal Democratic Party (LDP) has suffered in local elections, including in the key Tokyo municipality.
Opinion polls suggest the LDP could lose heavily to the opposition Democratic Party (DPJ) in the election.
A DPJ victory would end five decades of almost uninterrupted rule by the LDP.
''Although we received lots of support from party members and supporters in a series of local elections, including the Tokyo Metropolitan Assembly, we unfortunately failed to achieve our initial targets,'' Mr Aso told LDP legislators in a televised speech.
''I apologize for that once again.''
On Tuesday morning, his cabinet gave its formal backing to Mr Aso's plan to dissolve parliament and hold a general election.
Japan is in a deep recession and correspondents say that at times the prime minister has appeared indecisive.
ASO'S KEY MOMENTS
Sept 2008: Confirmed as PM
Nov 2008: Causes outrage by saying doctors lack common sense
Nov 2008: Alienates pensioners - a key constituency - by saying they "just eat and drink and make no effort"
Feb 2009: Economics minister says Japan facing worst economic crisis since WWII
April 2009: Introduces stimulus package after months of delay
July 2009: Tokyo election loss - fourth in recent weeks. DPJ has at least 12 percentage point lead in opinion polls
Last week, Mr Aso survived a no-confidence motion put forward by the opposition in the lower house. But the upper house, which is dominated by the opposition, passed a similar motion.
Mr Aso's position had already been weakened when the LDP lost control of Tokyo city council in elections on 12 July.
LDP rebels had sought to remove him before he could dissolve parliament, believing he was leading them to a historic defeat.
Polls published by the Asahi and Mainichi newspapers on Monday suggested that support for Mr Aso had continued to decline since previous surveys last month.
They showed him trailing Democratic Party leader Yukio Hatoyama.
Correspondents say the Democratic Party favours more independence from the US, a greater Japanese contribution to peacekeeping missions, and a smaller role for government.
Mr Aso is the fourth prime minister since the party won the last election to the lower house of parliament in 2005.