Tokyo stocks closed lower Monday as a cronyism and document-tampering scandal implicating Prime Minister Shinzo Abe caused political uncertainty and a slump in his cabinet's approval rating in recent polls.

The 225-issue Nikkei Stock Average dropped 195.61 points, or 0.90 percent, from Friday to close the day at 21,480.90, marking its lowest closing level since March 9.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, lost 16.66 points, or 0.96 percent, to finish at 1,719.97.

Despite an upbeat performance on Wall Street and the end of last week, investor sentiment was soured by media polls that the approval rating for Abe's Cabinet had tumbled by 9.4 percentage points from the previous poll conducted by Kyodo News, to 38.7 percent in a survey conducted over the weekend.

Local brokers noted that the ongoing scandals in which Abe is implicated could affect his chances of being reelected as the leader of the ruling Liberal Democratic Party in autumn and hence the prospect of becoming Japan's longest-serving prime minister.

They said that under this scenario, investors were concerned that a halt in the prime minster's "Abenomics" drive could adversely affect Japanese stocks in the long term, and political uncertainty in the short term turns international investors risk averse.

Precision instrument, securities and electric appliance-linked issues comprised those that declined the most by the close of play, and falling issues beat advancing ones by 1,710 to 311 on the First Section, with 50 ending the day unchanged.

On the main section on Monday, 1,206.63 million shares changed hands, dropping from Friday's volume of 1,388.06 million shares.

The turnover on the first trading day of the week came to 2,167.8 billion yen (20.50 billion U.S. dollars).