BEIJING — The Chinese Ministry of Public Security has punished at least 197 people in recent days for “spreading rumors” online, it said. Its announcement did not give details, but the accused have presumably been detained.

The so-called rumors were related to China’s continuing stock market uncertainty, the recent industrial explosions in Tianjin and the military parade scheduled for Thursday to commemorate the 70th anniversary of the end of World War II, the ministry said on Sunday. Xinhua, the state-run news agency, reported on Monday that the ministry’s actions were the core of a “special campaign” by the police.

The moves are an indication of the political sensitivities that have been aggravated in recent weeks by several volatile issues, among which the most painful for Chinese leaders have been the slowing economy and the market collapse.

Months ago, President Xi Jinping and other senior Chinese officials called for the military parade as a bravado display of nationalism, and scheduled Mr. Xi’s first state visit to the United States for September, but now both occasions are expected to be shadowed by the various crises that have shaken China this summer.