China announced Wednesday the opening of investigations into several top executives of state-owned real estate companies for "serious violations of discipline and the law," a euphemism used in the country for acts of corruption.

This is yet another blow to a key sector of the Chinese economy, which is already facing a slowdown in sales, a liquidity crisis, and buyers dissatisfied with long delivery times for properties.

The local bodies of the Chinese Communist Party's anti-corruption agency announced in separate statements that four leaders of real estate companies have been placed under investigation.

The targets of the investigations are Zhuang Yuekai, Chairman of the Board of C&D Real Estate; Shi Zhen, Chairman of the Urban Services Board of C&D; Liu Hui, Deputy General Manager of Shenzhen Talents Housing Group; and Tang Yong, former Chairman of the Board of Directors of China Resources Land.

All four are suspected of "serious violations of discipline and the law," the releases say, without adding further details.

This expression is often used by the authorities to denote acts of corruption or fraud, but can also denote, in some cases, disobedience to the CCP's political guidelines.

These investigations may "deal another blow to investor confidence and raise concerns about the internal management of certain public companies," said ANZ Bank analyst Ting Meng, quoted by Bloomberg news agency and the newspaper de Negócios.

These announcements come just a few months before the 20th CCP Congress, the most important event on China's political agenda, is held every five years.

This year, the Congress is expected to give CCP General Secretary Xi Jinping a third five-year term, breaking with the political tradition of the past decades.

Since taking over the CCP leadership in 2012, Xi has launched a vast anti-corruption campaign, which has resulted in the punishment of senior Party officials, leaders of public companies and organizations, or senior army officers.

In China, almost all personalities prosecuted for corruption are eventually convicted.