Vietnam’s two biggest cities, Ho Chi Minh City and Hanoi, are ramping up measures as dengue cases surge sharply, officials said Monday.

Hanoi reported 34 new infections last week, a rise from the previous week, with health officials warning of more cases as the city enters peak season, according to Xinhua.

In Ho Chi Minh City, six dengue-related deaths have been confirmed this year. The city logged 838 new cases last week, pushing the yearly total to 14,370—up over 150 percent from last year.

Residents are being urged to clear standing water and report mosquito breeding spots through a health app, Xinhua reported.