BEIJING — Chinese authorities have arrested an 18-year-old man from a village near the oasis city of Kashgar, in far western China, accusing him of inspiring and planning a fatal attack last month on the imam of the nation’s biggest mosque, according to state news media reports.

Reports from Chinese journalists in Xinjiang, the vast western region that includes Kashgar, said late Sunday that the police had detained the suspect, Aini Aishan, a member of the Uighur ethnic minority, while he was in the city of Khotan, another oasis settlement east of Kashgar. The arrest took place just two days after a fatal knife or ax attack July 30 on Jume Tahir, 74, the Uighur imam of the historic yellow-walled Id Kah Mosque.

The killing of the imam underscored the increasingly bloody nature of the ethnic conflicts in Xinjiang. This year, a growing number of terrorist-style attacks has shaken the region and cities elsewhere in China. The assaults have been linked to tensions between Uighurs, who mostly follow Sunni Islam, and Han, who make up the country’s dominant ethnic group.