CHENGDU -?Southwest China's Sichuan Province on Thursday reported two human H7N9 avian flu cases, bringing the total number of infections in the province to four this year.

The two patients were diagnosed in Suining city and they are both currently in a critical condition, said the provincial health and family planning commission.

Local authorities have taken disease control measures.

Sichuan reported its first H7N9 case in early February.

H7N9 is a bird flu strain first reported to have infected humans in China in March 2013. Infections are most likely to strike in winter and spring.