The Vietnamese province of Dong Nai on Monday declared a Zika outbreak at communal level.
The Dong Nai Health Department said from December 2016 to early January 2017, four cases of Zika infections were spotted in Vinh Thanh commune, Nhon Trach district.
The department noted that besides the four patients in the commune, the province had registered two other cases in other communes.
It added that at the end of 2016, Vietnam had detected 155 Zika cases, including 145 from Ho Chi Minh City.
Relevant agencies in the city and other localities hit by Zika outbreaks have been urging residents to kill mosquitoes and their larvae, use mosquito nets when sleeping, and minimise travel to affected areas.