Washington, March 2 : Rochelle Walensky, Director of the US Centers for Disease Control and Prevention (CDC), has warned that the country was at risk of losing its recent progress in the battle against the Covid-19 pandemic if states roll back health measures. "I am really worried about reports that more states are rolling back the exact public health measures we have recommended to protect people from Covid-19," she said in a statement on Monday. "At this level of cases with variants spreading, we stand to completely lose the hard earned ground we have gained," Xinhua news agency quoted the CDC chief as further saying. After weeks of tumbling case numbers, new infections are on the rise again, about 2 per cent more this past week compared to the previous week, according to Walensky. Similarly, the most recent seven-day average of deaths has also increased more than 2 per cent, to nearly 2,000 deaths per day. She called on the public to continue wearing well-fitting masks and taking other public health prevention actions. "It is so critical that we remain vigilant and consistently take all of the mitigation steps we know work to stop the spread of Covid-19 while we work our way toward mass vaccination," the CDC Director added. The US is still the worst-hit country with the world's highest number of cases and deaths at 28,659,784 and 514,333, respectively, as of Tuesday morning, according to the Johns Hopkins University. /IANS