The latest cluster of COVID-19 infections in Wuhan City, central China's Hubei Province, is linked to the highly contagious Delta variant, local government officials said at a press briefing on Wednesday. 

Wuhan on Monday reported seven positive cases among migrant workers. Genome sequencing of two cases from the seven have finished and showed high similarity to the cases of Delta variant recently found in east China's Jiangsu Province.

Since July 31, Hubei Province has logged 15 local COVID-19 infections, 12 of which were found in its capital city Wuhan. 

At another press briefing on Tuesday, the Hubei government revealed that existing positive cases locally found are all related to infections in Jiangsu Province according to epidemiological investigation and gene sequencing results. 

Once hard-hit by COVID-19, Wuhan had not reported a locally transmitted case for over a year before Monday.

The Chinese city launched citywide virus testing campaign on Tuesday following the resurgence.