TOKYO (BNO NEWS) -- Japanese Prime Minister Naoto Kan resigned on Friday after almost 15 months in office amid sinking approval ratings, NHK Television reported.

Kan said he is stepping down as the leader of the ruling Democratic Party after the passage of two key bills. Earlier in the day, a bill authorizing the government to issue deficit-covering bonds and another promoting renewable energy were passed.

The premier said he did everything he should have done and promised to keep working hard, both as a politician and as a member of Japanese society. He also said he wants to help Japan recover from the effects of the massive quake, tsunami and nuclear disaster.

The Democratic Party is due to elect its new chief on Monday, and Kan will remain prime minister until a successor has been chosen.

In late June, the Democratic Party of Japan and major opposition parties, including the Liberal Democratic Party and the New Komeito party, agreed that Kan should resign by the end of August. In the beginning of June, Kan survived a no-confidence vote after abruptly announcing his intention to resign after the nuclear crisis and the earthquake and tsunami relief efforts were concluded.

Japan has been facing an ongoing nuclear crisis since the Fukushima Daiichi nuclear power plant was severely damaged on March 11 when a 9.0-magnitude earthquake and a subsequent tsunami devastated the country. The disaster disabled the cooling systems of the plant, and radioactive elements leaked into the sea and were later found in water, air and food products in some parts of Japan.

At least 23,482 people were killed, while 8,069 people remain missing. There are still more than 88,000 people who are staying in shelters in 21 prefectures around Japan.