Tokyo - Japanese Prime Minister Shinzo Abe announced on Monday he will call a snap election for parliament's more powerful lower house for next month.Abe said at a news conference that he will dissolve the chamber on Thursday when it convenes after a three-month summer recess. The election is to be held October 22.Support ratings for Abe's government have started to rebound after attacks on him over cronyism scandals faded during parliament's recess. Also, opposition parties are regrouping and unprepared for an election.Opposition lawmakers have said there is no need to hold an election now.Tokyo's popular governor announced earlier on Monday that she is launching a new political party to challenge Abe's ruling party in the election.Yuriko Koike said she is heading the Hope Party and plans to send candidates to vie for some of the 475 seats in the lower house.She said her party will be conservative and push for transparency in government, women's advancement, elimination of nuclear energy and other reforms. Several parliamentarians, including defectors from the main opposition Democratic Party, have announced their intention to join her party."This is going to be a new force formed by members aiming to achieve reforms and conservativism," Koike said. "We are going to create a Japan where there is hope for everyone that tomorrow will certainly be better than today."Koike's regional Tokyoites First no Kai group won a landslide victory in the city assembly election in July, dealing a major blow to Abe's party. On Monday, she reminded voters of the scandals that led Abe's government's support ratings to fall below 30% in July.Support for Abe's party has since rebounded, helped somewhat by a Cabinet reshuffle last month.The Democrats, which held power in 2009-2012, have lost ground since then, largely due to party disagreements.