Japanese Prime Minister Taro Aso told ruling party leaders Monday he will dissolve parliament and hold general elections next month, following a crushing defeat for his party in Tokyo municipal polls considered a barometer of voter sentiment.

The decision came as opposition parties, emboldened by a surge in popularity, submitted a joint no-confidence motion in parliament against the prime minister and his Cabinet.

Aso told leaders of his Liberal Democratic Party he would likely dissolve the powerful lower house of the legislature next week, with a general election to be held on Aug. 30, according to Osamu Sakashita, a spokesman at the prime minister's office.

The move was widely seen as a last-ditch attempt to keep the ruling party in power after the Liberal Democrats and their coalition lost their majority Sunday in the Tokyo Metropolitan Assembly. The assembly elections have been closely watched as a bellwether of what's ahead for Aso's party.

Meanwhile, the opposition, led by the Democratic Party of Japan, submitted the no-confidence motion to the powerful lower house of parliament, said party spokesman Toshiaki Oikawa. The motion was not expected to pass and was instead seen as a symbolic action to embarrass Aso.

Sunday's Tokyo Metropolitan Assembly vote does not directly affect the outcome of the upcoming national election, but the defeat deepened turmoil in the ruling party, with many lawmakers calling for fresh leadership heading into elections. Others were already jumping ship — lawmaker Kotaro Nagasaki submitted his withdrawal from the party on Monday.