Heilongjiang province declared a state of emergency over the coronavirus outbreak, local officials said on Tuesday.

"Faced with a complex and severe epidemic prevention and control situation across the province, we should focus on preventing further spread of the virus both inside and outside the province," said Zhang Qingwei, Party secretary of Heilongjiang, at an epidemic prevention and control conference on Tuesday night.?

Locally transmitted confirmed cases, along with asymptomatic carriers of the coronavirus, have continued to increase in the recent outbreak since the first asymptomatic case was reported on Sunday in Suihua city's Wangkui county.

As of Wednesday afternoon, the province had reported 17 confirmed and 48 asymptomatic cases since Sunday.

Mudanjiang's Linkou county reported four new local asymptomatic carriers on Wednesday afternoon, according to the county's center for disease control and prevention. All the patients were connected in some way to Wangkui, the center said.

Affected cities in the province began to implement measures to prevent spreading.

All residential communities and villages in Suihua were locked down on Tuesday afternoon, according to the city's epidemic prevention and control headquarters.

Bus and railway services for passengers were suspended.

The city of Yichun has began large-scale coronavirus testing for all residents on Wednesday.

A resident surnamed Tian in Qinggang county, Suihua, was given an administrative punishment for hiding his nephew's travel history in Wangkui and the fact that his nephew is a classmate of an asymptomatic carrier who was identified in Wangkui.

"Tian's behavior caused a delay of more than 28 hours in epidemic prevention and control, including nucleic acid testing and quarantines for close contacts. This brought great risk of spreading the virus," a statement from the local government said.

Weihai, Shandong province, reported an asymptomatic carrier related to Wangkui on Wednesday, the city's health commission said.

The 22-year-old male patient, a deliveryman for a local company, returned to Weihai from Wangkui on Saturday. He tested positive for the coronavirus on Tuesday and was diagnosed as asymptomatic.

As of 8 am on Wednesday, the city had traced 184 close contacts and collected 300 nucleic acid test samples, all of which came back negative.