Chinese stocks plunged on Thursday, with investor optimism weakened amid the absence of a clear timeline to the end of the war in Iran.

The Shanghai Composite Index, the main gauge of Chinese stocks, retreated 0.7% or by 29.27 points to 3,919.29. The Shenzhen Component Index slid 1.6% or by 219.58 points to 13,486.94.

U.S. President Donald Trump earlier said his administration would need two to three weeks to finish the war in Iran.

However, in his televised speech, Trump only said he would finish the job "very fast," without mentioning a timeline, Reuters reported separately.

On the data front, prices of new homes across 100 cities in China rebounded 0.05% month on month in March but jumped 2.24% year over year to 17,115 yuan per square meter.

In corporate news, SAIC Motor's (SHA:600104) shares slipped 3% despite net profit skyrocketing 506% year over year to 10.1 billion yuan from 1.67 billion yuan.

Hisense Visual Technology (SHA:600060) is also facing a probe by the U.S. International Trade Commission following a patent infringement complaint filed by Las Vegas-based InnoTV Labs.