Uighur exiles from China urged the International Criminal Court on Monday to investigate Beijing for genocide and crimes against humanity, the first-ever attempt to use international law to hold China’s ruling Communist Party accountable for its draconian crackdown on the Muslim minority.

The policies of Xi Jinping, the Communist Party leader, have put Muslim minorities in China’s western region of Xinjiang under a pervasive net of surveillance, detention and social re-engineering. As many as one million ethnic Uighurs and members of other Muslim minorities have been held in internment camps in the region, drawing growing global condemnation.

The authorities are also pursuing an expansive and troubling campaign to drastically reduce the birthrate among minority groups in Xinjiang using forced sterilisation and abortions, according to an investigation by The Associated Press and Adrian Zenz, a German researcher.

Rodney Dixon, a British lawyer leading the case said the complaint against Beijing included evidence of forced deportations and extraterritorial arrests by Chinese agents, gathered from witnesses and victims, reports from the United Nations and organizations such as Amnesty International and exile groups.

“The prosecutor needs to investigate genocide,” Mr. Dixon said. “If you capture people, and you have a campaign to suppress them and you sterilize them, it is a campaign which intends to dilute and destroy their identity as a group.”